JP2001237175A - Proximity effect correction method, reticle, and method of manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proximity effect correction method which is capable of realizing a pattern of high dimensional accuracy. SOLUTION: Design patterns to be formed on a sensitive substrate are set. A pattern smaller than four times as large as the amount of fading of a charged particle beam used in a primary exposure process is extracted from the design patterns, and a pattern shape correction for correcting a proximity effect is calculated. Primary exposure reticle pattern data are formed in reference to the calculation result of the pattern shape correction. A primary exposure reticle for actual use is formed on the basis of the above pattern data. In this case, by the use of a variable forming beam-type electron beam drawing device, a dose adjustment or a shape correction or the like is carried out. Using this reticle, the sensitive substrate is subjected to a primary light exposure process by the use of a self-projection or split transfer-type electron beam projection exposure system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting a proximity effect in charged particle beam exposure used in lithography of semiconductor integrated circuits and the like. Further, the present invention relates to a reticle modified by such a proximity effect correction method. Further, the present invention relates to a device manufacturing method for performing a lithography process using a charged particle beam exposure method involving such a proximity effect correction method.

[0002]

2. Description of the Related Art At present, exposure of each wafer (sensitive substrate) in lithography of a semiconductor integrated circuit is mainly performed by a so-called stepper using ultraviolet rays. Charged particle beam exposure is used for drawing a reticle mounted as a pattern master on a stepper, but has not been used for a mass production lithography process of a wafer.
However, recently, in order to expose a highly integrated and ultra-fine pattern, it has been proposed to use electron beam transfer exposure for each wafer.

However, electron beam exposure has a drawback of low throughput, and various techniques have been developed to solve the drawback. At present, a figure portion batch exposure method called cell projection, character projection or block exposure has been put to practical use. In the figure partial batch exposure method, a repetitive circuit small pattern (about 5 μm square on a wafer) is repeatedly transferred using a mask in which a plurality of similar small patterns are formed, with one small pattern as one unit. Perform exposure.
However, even in this method, the variable shaping method is used for pattern portions having no repeatability. For this reason, it is impossible to obtain a desired throughput in the mass production lithography process of the wafer.

As an electron beam transfer exposure system aiming at a much higher throughput than the graphic partial batch exposure system, a reticle having a circuit pattern of an entire semiconductor chip is prepared, and a certain area of the reticle is irradiated with an electron beam. In addition, an electron beam reduction transfer device that reduces and transfers an image of a pattern in the irradiation range by a projection lens has been proposed.

In this type of apparatus, when the entire area of the mask is irradiated with an electron beam to transfer the pattern at once, the pattern cannot be transferred with high accuracy. In addition, it is difficult to manufacture a mask serving as an original. Therefore, a method which has been studied vigorously recently does not expose one die (chip on a wafer) or a plurality of dies at once, but has a large optical field as an optical system, but a pattern has a small area (sub-area). This is a method in which transfer exposure is performed by dividing into (field) (herein, referred to as a split transfer method). At this time, for each of the small areas, exposure is performed while correcting aberrations such as the focal point of the image of the small area formed on the surface to be exposed and the field distortion. This makes it possible to perform exposure with high resolution and accuracy over an optically wide area as compared with batch transfer of the entire die.

When a sensitive substrate such as a wafer is irradiated with a charged particle beam for exposure, there is a proximity effect in which the actual exposure amount changes according to a nearby pattern distribution due to reflected electrons or ions from the substrate. . The proximity effect spreads the charged particles incident on the sensitive substrate surface while scattering,
This occurs when the energy stored in a predetermined position is reduced or charged particles incident on an exposed portion are widely scattered to give energy to a surrounding non-exposed portion. To solve this, there are the following methods. GHOS that performs secondary exposure so that the energy fog (background dose) on the sensitive substrate is uniform
T-exposure Dose correction for changing and adjusting the irradiation dose during primary exposure so that the amount of energy stored on the sensitive substrate is desirable Shape correction for changing the pattern shape given on a mask or reticle

On the other hand, the charged particle transfer optical system has blur. Blurring is caused by geometrical aberrations such as spherical aberration existing as in the case of ordinary light, and repulsion of charged particles in a beam due to Clone interaction. In general, blur caused by geometric aberration increases as the distance from the optical axis to the beam increases. In an exposure apparatus of a divisional projection transfer system for projecting and exposing a part of a reticle at a time, the blur increases as the center of a subfield (collective exposure area), which is a unit of one transfer exposure, is farther from the optical axis. In addition, even within a subfield, there is a general tendency that blur is greater at the end than at the center. Also, the blur due to the clone interaction tends to increase as the pattern area increases and the current amount increases. Such a phenomenon causes an unintended increase or decrease in line width, which is a problem.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and has as its object to provide a proximity effect correction method and the like which can achieve high pattern dimensional accuracy. .

[0009]

In order to solve the above problems, a first proximity effect correction method of the present invention is to selectively irradiate a charged particle beam onto a substrate (sensitive substrate) coated with a resist layer. And correcting a proximity effect generated by backscattering of charged particles in the sensitive substrate when forming a pattern by performing; setting a pattern (design pattern) to be formed on the sensitive substrate; Exposure pattern data (data of a figure position, a figure width, and an irradiation dose) corresponding to the pattern is set after pattern shape correction for proximity effect correction is performed, and based on the exposure pattern data, a primary image is formed on the sensitive substrate. Performing exposure, and setting pattern data for GHOST correction for uniforming the dose distribution due to backscatter of charged particles during the primary exposure,
Based on the GHOST correction pattern data, a secondary exposure is performed on the sensitive substrate that has been subjected to the primary exposure.

In a second proximity effect correction method according to the present invention, when a pattern is formed by selectively irradiating a charged particle beam onto a substrate (sensitive substrate) coated with a resist layer, the charged particles A pattern to be formed on a sensitive substrate (design pattern), and exposing pattern data (figure position, figure width and pattern width) corresponding to the design pattern. (Irradiation dose data) is set after adding a dose correction for proximity effect correction, and a primary exposure is performed on the sensitive substrate based on the exposure pattern data, and a backscatter of charged particles at the time of the primary exposure is performed. GHOST correction pattern data for uniformizing the dose distribution due to the GHOST correction pattern, based on the GHOST correction pattern data, And characterized by applying light.

According to a third proximity effect correction method of the present invention, a pattern to be transferred onto a substrate (sensitive substrate) coated with a resist layer is formed on a reticle, and the charged particle beam patterned using the reticle is formed. When irradiating a pattern on the sensitive substrate to transfer the pattern, to correct the proximity effect caused by backscattering of charged particles in the sensitive substrate,
A proximity effect correction method for correcting exposure pattern data (data of a figure position, a figure width, and an irradiation dose) at the time when the reticle is manufactured by charged particle beam exposure, and preliminarily adjusting each part of the pattern on the reticle. Setting a pattern (design pattern) to be formed on the sensitive substrate,
Exposure pattern data of a pattern to be formed on a reticle corresponding to the design pattern is set after adding a pattern shape correction for proximity effect correction at both a reticle drawing exposure and a transfer exposure to a sensitive substrate. Producing a reticle by exposing based on the exposure pattern data, performing primary exposure on the sensitive substrate using the obtained reticle,
GHOST correction pattern data for uniformizing the dose distribution of the charged particles by the backscatter at the time of the primary exposure is set, and based on the GHOST correction pattern data, The next exposure is performed.

In the proximity effect correction method, the shape of the reticle pattern can be adjusted by dose adjustment when drawing and exposing the reticle for primary exposure.

In the proximity effect correction method, the shape of the reticle exposure pattern data can be adjusted when the reticle for primary exposure is subjected to drawing exposure.

In the proximity effect correction method of the present invention,
The blur amount of the charged particle beam applied to the sensitive substrate is 4
Shape correction can be performed only on a pattern having a size of twice or less.

In the proximity effect correction method of the present invention,
The blur amount of the charged particle beam applied to the sensitive substrate is 4
Dose correction can be performed only on a pattern having a size of twice or less.

A reticle according to the present invention is characterized in that the proximity effect correction is performed by the above method.

A device manufacturing method according to the present invention is characterized in that, in a lithography step using a charged particle beam, proximity effect correction is performed by the above method.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, description will be made in the case of a reticle transfer exposure system, but most of the basic methods of the present invention can be applied to a system in which direct exposure is performed without using a reticle.

First, an outline of a division transfer type electron beam projection exposure technique, which is one of the background arts of the present invention, will be described with reference to the drawings. FIG. 7 is a diagram showing an outline of an imaging relationship and a control system in the entire optical system of the electron beam projection exposure apparatus of the division transfer system.

An electron gun 10 arranged at the uppermost stream of the optical system
1 emits an electron beam downward. Below the electron gun 101, two stages of condenser lenses 102 and 103 are provided, and the electron beam is converged by these condenser lenses 102 and 103 and crossed over a blanking aperture 107.
O. Image formation.

Below the condenser lens 103 in the second stage,
A rectangular opening 104 is provided. This rectangular aperture (illumination beam shaping aperture) 104 is used to form one subfield (a pattern small area which is one unit of exposure,
Only the illumination beam that illuminates the primary exposure area) is passed. Specifically, the opening 104 shapes the illumination beam into, for example, a square of 0.5 to 5 mm square in reticle size conversion. The image of the opening 104 is formed on the reticle 110 by the lens 109.

Below the beam forming aperture 104, a blanking deflector 105 is arranged. The deflector 105 deflects the illumination beam to hit the non-opening portion of the blanking opening 107 so that the beam does not hit the reticle 110.
Below the blanking opening 107, an illumination beam deflector 108 is arranged. The deflector 108 mainly scans the illumination beam sequentially in the horizontal direction (X direction) in FIG. 7 to illuminate each subfield of the reticle 110 within the field of view of the illumination optical system. An illumination lens 109 is arranged below the deflector 108. The illumination lens 109 forms an image of the beam shaping aperture 104 on the reticle 110.

Although only one subfield on the optical axis is shown in FIG. 7, reticle 110 actually extends in a plane perpendicular to the optical axis (XY plane) and has many subfields. On the reticle 110, a pattern (chip pattern) forming one semiconductor device chip as a whole is formed.

The reticle 110 is mounted on a movable reticle stage 111. By moving the reticle 110 in a direction perpendicular to the optical axis (YX direction), the reticle 110 spreads over a wider area than the field of view of the illumination optical system. Each subfield can be illuminated. The reticle stage 111 is provided with a position detector 112 using a laser interferometer,
The position of reticle stage 111 can be accurately grasped in real time.

Below the reticle 110, a projection lens 115 and
119 and a deflector 116 are provided. The electron beam passing through a certain subfield of the reticle 110 is
5, 119 and the deflector 116 form an image at a predetermined position on the wafer 123. An appropriate resist is applied on the wafer 123, the resist is given an electron beam dose, and the pattern on the reticle is reduced and transferred onto the wafer 123.

A crossover image CO is formed at a point that internally divides the area between the reticle 110 and the wafer 123 at a reduction ratio.
A contrast aperture 118 is provided at the crossover image position. The opening 118 blocks the electron beam scattered by the non-pattern portion of the reticle 110 from reaching the wafer 123.

A backscattered electron detector 122 is disposed directly above the wafer 123. This backscattered electron detector 122 is
The amount of electrons reflected by the surface to be exposed and the mark on the stage is detected. For example, by scanning a mark on the wafer 123 with a beam that has passed through a mark pattern on the reticle 110 and detecting reflected electrons from the mark at that time, the relative positional relationship between the reticle 110 and the wafer 123 can be known. .

The wafer 123 can be moved in the X and Y directions via an electrostatic chuck (not shown).
4 is placed on. By synchronously scanning the reticle stage 111 and the wafer stage 124 in directions opposite to each other, a large number of subfields arranged in the chip pattern can be sequentially exposed beyond the field of view of the optical system. Note that the wafer stage 124 is also provided with a position detector 125 similar to the above-described reticle stage 111.

Each of the lenses 102, 103, 109, 115, 119 and each of the deflectors 105, 108, 116 are provided with a coil power controller 102a, 10a.
It is controlled by the controller 131 via 3a, 109a, 115a, 119a and 105a, 108a, 116a. Also, the reticle stage 111 and the wafer stage 124 are
It is controlled by the control unit 131 via 111a and 124a. The stage position detectors 112 and 125 send signals to the controller 131 via interfaces 112a and 125a including an amplifier and an A / D converter. Also, the backscattered electron detector 122 is connected to the controller 131 via the same interface 122a.
Send a signal to

The controller 131 grasps the control error of the stage position, and corrects the error by the image position adjusting deflector 116. Thus, the reduced image of the subfield on reticle 110 is accurately transferred to the target position on wafer 123.
Then, the subfield images are joined on the wafer 123, and the entire chip pattern on the reticle is transferred onto the wafer.

Next, a proximity effect correction method according to an embodiment of the present invention will be described. FIG. 1 shows that a reticle is manufactured according to the proximity effect correction method according to one embodiment of the present invention, and the wafer is subjected to primary exposure using the reticle, and then GH is used.
9 is a flowchart of a process for performing OST correction exposure. First, a design pattern to be formed on the sensitive substrate is set (S1). Next, a pattern smaller than four times the blur amount of the charged particle beam at the time of performing the primary exposure is extracted from the design patterns (S2), and such a small pattern (S3) is used for correcting the proximity effect. The pattern shape correction is calculated (S4). On the other hand, among the design patterns, the shape correction is not performed on the pattern having a size four times or more the blur amount (the other pattern (S11)). Next, reticle pattern data for primary exposure is prepared with reference to the calculation result of the pattern shape correction (S5). Based on the reticle pattern data, a reticle for primary exposure actually used is manufactured (S6). At this time, dose adjustment or shape correction is performed using a variable shaped beam type electron beam writing apparatus. Then, using this reticle, primary exposure is performed on the sensitive substrate using an electron beam projection exposure apparatus of the cell projection or division transfer type (S7).

On the other hand, for GHOST correction for making the dose distribution of charged particles due to backscatter uniform, pattern data for that is prepared (S12). Then, a reticle for secondary exposure is actually produced based on the pattern data (S13). Then, using the reticle, the sensitive substrate that has been subjected to the primary exposure is subjected to secondary exposure (S14).

Next, a description will be given of a proximity effect correction method according to another embodiment of the present invention. FIG. 2 is a flowchart illustrating steps of a proximity effect correction method according to another embodiment of the present invention. This example is an example in which primary exposure of a wafer is performed by writing using a variable shaped beam method. First, a design pattern to be formed on the sensitive substrate is set (S21). Next, a pattern smaller than four times the blur amount of the charged particle beam at the time of performing the primary exposure is extracted from the design patterns (S22).
For such a small pattern (S23), a dose correction for proximity effect correction is calculated (S24). On the other hand, the dose correction is not performed on the pattern (the other pattern (S31)) having a size four times or more the blur amount among the design patterns. Next, with reference to the calculation result of the pattern dose correction, the sensitive substrate is subjected to primary exposure by performing dose correction using a variable shaped beam type electron beam lithography apparatus (S2).
Five).

On the other hand, for GHOST correction for making the dose distribution of charged particles due to backscatter uniform, pattern data for that purpose is prepared (S32). Then, a reticle for secondary exposure is actually manufactured based on the pattern data (S33). Then, the reticle is subjected to secondary exposure on the sensitive substrate subjected to the primary exposure (S34).

FIG. 3A is a plan view showing a predetermined pattern (design pattern) realized on a wafer (sensitive substrate) in the proximity effect correction method according to one embodiment of the present invention.
In the figure, from left to right, a thin line pattern (line) 1, a narrow space 2, a wide line pattern (pad) 3, a wide space 4, and a thin line pattern (line) 5 are shown. ing. The width of line 1, line 5 and space 2 is 100 nm. The width of the pad 3 is 50 μm.
The width of the space 4 is 70 μm. In addition, the scale of the figure is adjusted for easy understanding.

A subfield of 250 μm square including such a pattern is transferred by a divided projection type charged particle beam optical system. In general, 1/4 or 1/5 is often used as the magnification of the optical system, but here, for simplicity, one-to-one 100 kV
Consider an electron beam transfer optical system.

FIG. 3B shows an energy profile immediately after passing through the reticle. The vertical axis (Y axis) is energy, and the horizontal axis (X axis) is horizontal position. In this figure, since the blur of the optical system is not added, the energy profile is very sharp against a change in position. Energy profile DW immediately after passing through the reticle
(x) is a function of x and is represented by the following equation. DW (x) = 1.0 (0.0 ≦ x ≦ 0.1, 0.2 ≦ x ≦ 50.2, 120.2 ≦ x
≦ 120.3) DW (x) = 0.0 (x <0.0, 0.1 <x <0.2, 50.2 <x <120.2, 120.
3 <x)

Here, immediately before the light enters the sensitive substrate surface,
Since the energy profile becomes dull due to the blur of the optical system, the blurred energy profile DR (x) was calculated by the following equation.

(Equation 1) Here, β is a standard deviation appropriately determined when the blur of the optical system is represented by a Gaussian distribution.

As described above, the blur of the optical system is determined by the amount of deflection, the subfield size, the aperture ratio of the pattern, and the like. Here, for simplicity, it is determined by the distance r from the center of the subfield in the subfield. Assuming this is expressed by the following equation. blur (nm) = 70nm + 0.25 × r (μm) According to this equation, the size of the blur at the center of the subfield is 70 nm, and a point on the subfield (x = 120 μm, y = 0μ
The size of the blur in m) is 100 nm.

FIG. 4 is a diagram showing the energy profile DR (x) immediately before the light enters the sensitive substrate surface. The energy on the vertical axis is when the proximity effect and blur are considered.
The maximum value that can be accumulated on the sensitive substrate surface was standardized (the maximum value was set to 1). This maximum value is equal to the value of the amount of stored energy at the pattern center when a pattern sufficiently large than the scattering range in the substrate or the blur of the optical system is printed. 4 (A), (B) and (C) respectively show x = −0.1 to 0.3 μm, x
FIG. 4 is a diagram showing an energy profile DR (x) in a range of = 50.0 to 50.4 μm and x = 120.0 to 120.4 μm. (B) and (C) are closer to the edge of the subfield than (A) and are more blurred than (A), so that the slope of the energy profile is gentler.

The incident charged particles are scattered in the sensitive substrate,
Causes proximity effect. The energy amount E (x) stored in the sensitive substrate after scattering is represented by, for example, the following equation. E (x) = Eb (x) + Ef (x)

(Equation 2)

(Equation 3) Here, η is the backscattering coefficient, σb is the backscattering diameter, and σf is the forward scattering diameter. Using electrons as charged particles, the acceleration voltage
As a typical value at 100 keV, η =
0.4, σb = 31.2 μm, σf = 7 nm are used for calculation.

FIG. 5 is a diagram showing the energy amount E (x) finally stored in the sensitive substrate when the proximity effect is considered. As in the case of FIG. 4, FIGS. 5A, 5B, and 5C show x = −0.1 to 0.3 μm, x = 50.0 to 50.4 μm, and x = 12, respectively.
FIG. 4 is a diagram showing an energy profile E (x) in a range of 0.0 to 120.4 μm. In an ideal case where there is no manufacturing error in the process, it can be considered that a pattern is formed in a portion of the energy profile exceeding a properly determined threshold, and is not formed in a portion not exceeding the threshold. Lines 40, 41, and 42 in FIG. 5 are thresholds drawn so that the edge position of each part of the pattern formed in each area coincides with a predetermined position. Although the values of the thresholds 40 and 41 are almost the same, the threshold 42 is significantly different from the other two, so when the thresholds are set near 40 and 41, the line pattern 5 shown in FIG.
Is smaller than a predetermined line width. Conversely, when the threshold value indicated by 42 is taken, the line pattern 1 shown in FIG. 3 becomes thicker, the space 2 becomes narrower, and the width of the pad 3 becomes thicker. In addition, as the line width changes, the edge position of each part of the pattern naturally deviates greatly from the predetermined position.

A case in which GHOST exposure is performed on the above-described drawing will be described. FIG. 6 is a diagram in which GHOST exposure is performed on the energy profile of FIG. This figure is also shown in FIG.
6 (A), (B), and (C) respectively show x = −0.1
FIG. 4 is a diagram showing an energy profile E (x) in a range of 0.3 μm, x = 50.0 to 50.4 μm, and x = 120.0 to 120.4 μm. The solid line shows the energy profile in the state of FIG. 5, and the broken line shows the energy profile after GHOST exposure. In the GHOST exposure, the reverse pattern is blurred to the extent of the backscatter, and the secondary exposure is performed with a predetermined exposure amount.

As is apparent from the figure, when the GHOST exposure is performed, the level of the fog (background dose) becomes uniform throughout. For a figure whose line width is sufficiently large compared to the blur of the primary pattern, the maximum intensity portion also has a constant level as shown in FIG. Therefore, for such a pattern, if an appropriate threshold value (for example, threshold values 60, 61, 62 indicating a level of about 0.6 in FIG. 6) is set as the development level, a predetermined size can be obtained regardless of the blur amount. However, if the dimension of the line width is not so large compared to the blur,
For example, if the dimension of the line width is smaller than three times the blur amount, FIG.
4, the maximum intensity portion does not reach the maximum intensity level in FIG. This state is, of course, the pattern dimensions,
It depends on the amount of blur. In such a case, accurate dimensions cannot be obtained even if development is performed at a predetermined threshold value.

In order to avoid this, in this embodiment, the primary pattern is corrected only for the small pattern as described above. After applying dimensional correction to the pattern and developing it,
The dimensions of the exposure pattern are corrected so as to obtain a predetermined dimension. Since it is not necessary to perform dimensional correction for all patterns, the time for correction calculation processing can be reduced. The pattern size correction is performed by correcting the size of the reticle in the case of the transfer exposure method of the present embodiment. To correct the size of the reticle, there are a method of correcting the shape of reticle pattern data for reticle exposure, and a method of adjusting the dose amount during reticle exposure to adjust the size of the completed reticle pattern. The blur amount is given as a parameter from the outside, but may be a constant value or a blur table may be given as an amount that changes according to the position.

Next, an embodiment of a device manufacturing method using the above-described proximity effect correction method will be described. FIG. 8 shows a flow of manufacturing micro devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.).

In step 1 (circuit design), a circuit of a semiconductor device is designed. Step 2 (mask fabrication) forms a mask on which the designed circuit pattern is formed. At this time, beam blur due to the proximity effect or the space charge effect may be corrected by locally resizing the pattern. Step 3 (wafer manufacturing)
Then, a wafer is manufactured using a material such as silicon.

Step 4 (oxidation) oxidizes the surface of the wafer. Step 5 (CVD) forms an insulating film on the wafer surface. Step 6 (electrode formation) forms electrodes on the wafer by vapor deposition. Step 7 (ion implantation) implants ions into the wafer. In step 8 (resist processing), a photosensitive agent is applied to the wafer. In step 9 (electron beam exposure), the circuit pattern of the mask is printed and exposed on the wafer by the electron beam transfer device using the mask created in step 2. Steps
In step 10 (light exposure), the circuit pattern of the mask is printed and exposed on the wafer by an optical stepper using the light exposure mask similarly formed in step 2. In step 9,
The above-described proximity effect correction method is used.

In step 11 (development), the exposed wafer is developed. In step 12 (etching), portions other than the resist image are selectively removed. Step 13 (resist stripping) removes unnecessary resist after etching. By repeating steps 4 to 13, multiple circuit patterns are formed on the wafer.

Step 14 (assembly) is called a post-process,
This is a process of forming a semiconductor chip using the wafer manufactured by the above process, and an assembly process (dicing,
Bonding), a packaging step (chip encapsulation), and the like. In step 15 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 14 are performed. Through these steps, a semiconductor device is completed and shipped (step 16).

Although the proximity effect correction method and the like according to the embodiment of the present invention have been described with reference to FIGS. 1 to 8, the present invention is not limited to this, and various changes can be made. it can.

[0052]

As is apparent from the above description, according to the present invention, the dimensional deviation of the pattern caused by the proximity effect and blurring of the optical system can be corrected with high accuracy by a short time correction calculation. .

[Brief description of the drawings]

FIG. 1 is a flowchart of a process for producing a reticle according to a proximity effect correction method according to one embodiment of the present invention, performing primary exposure on a wafer using the reticle, and then performing GHOST correction exposure.

FIG. 2 is a flowchart illustrating steps of a proximity effect correction method according to another embodiment of the present invention.

FIG. 3A is a plan view showing a predetermined pattern (design pattern) realized on a wafer (sensitive substrate) in the proximity effect correction method according to one embodiment of the present invention. FIG.
(B) is a diagram showing an energy profile immediately after passing through a reticle.

FIG. 4 is a diagram showing an energy profile DR (x) immediately before being incident on a sensitive substrate surface.

FIG. 5 is a diagram illustrating an energy amount E (x) finally stored in a sensitive substrate when the proximity effect is considered.

FIG. 6 is a diagram in which GHOST exposure is performed on the energy profile of FIG. 5;

FIG. 7 is a diagram showing an outline of an imaging relationship and a control system in the entire optical system of the electron beam projection exposure apparatus of the division transfer system.

FIG. 8 shows a flow of manufacturing a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin-film magnetic head, a micromachine, or the like).

[Explanation of symbols]

1, 5 line pattern (line) 2, 4 space 3 line pattern (pad) 40, 41, 42 threshold 60, 61, 62 threshold 101 electron gun 102, 103 condenser lens 104 illumination beam shaping aperture 105 blanking deflector 107 Ranking aperture 108 Deflector 109 Condenser lens 110 Reticle 111 Reticle stage 112 Reticle stage position detector 115 First projection lens 116 Image position adjustment deflector 118 Contrast aperture 119 Second projection lens 122 Backscattered electron detector 123 Wafer 124 Wafer stage 125 Wafer Stage position detector 131 Controller

Claims (9)

[Claims] When a pattern is formed by selectively irradiating a charged particle beam onto a substrate (sensitive substrate) coated with a resist layer, a proximity effect caused by backscattering of charged particles in the sensitive substrate. A pattern to be formed on a sensitive substrate (design pattern) is set, and the exposure pattern data (graphic position, graphic width, and irradiation dose data) corresponding to the design pattern is corrected for proximity effect correction. To perform a primary exposure on the sensitive substrate based on the exposure pattern data, and to uniform the dose distribution by backscatter of charged particles during the primary exposure. GHOST correction pattern data is set, and based on the GHOST correction pattern data, a secondary exposure is performed on the sensitive substrate that has been subjected to the primary exposure. Effect correction method. 2. A proximity effect caused by backscattering of charged particles in a sensitive substrate when a pattern is formed by selectively irradiating a charged particle beam onto a substrate (sensitive substrate) coated with a resist layer. A pattern to be formed on a sensitive substrate (design pattern) is set, and the exposure pattern data (graphic position, graphic width, and irradiation dose data) corresponding to the design pattern is corrected for proximity effect correction. To perform a primary exposure on the sensitive substrate based on the exposure pattern data, and to uniform the dose distribution by backscatter of charged particles during the primary exposure. Proximity effect, wherein GHOST correction pattern data is set, and a secondary exposure is performed on the sensitive substrate that has been subjected to the primary exposure based on the GHOST correction pattern data. Positive way. 3. A pattern to be transferred on a substrate (sensitive substrate) coated with a resist layer is formed on a reticle, and a charged particle beam patterned using the reticle is irradiated onto the sensitive substrate to form a pattern. In order to correct the proximity effect that occurs when charged particles are backscattered in the sensitive substrate when transferring the reticle, the exposure pattern data (figure position, figure width, irradiation dose Is a proximity effect correction method in which each part of the pattern on the reticle is adjusted in advance by correcting the data of the reticle; a pattern (design pattern) to be formed on the sensitive substrate is set; A pattern for correcting the proximity effect of the exposure pattern data of the pattern to be formed on the reticle at the time of reticle drawing exposure and transfer exposure to the sensitive substrate. The reticle is set based on the shape pattern correction, and the reticle is exposed based on the exposure pattern data. The reticle is used to perform primary exposure, and the charged substrate at the time of the primary exposure is subjected to primary exposure. GHOST correction pattern data for equalizing the dose distribution by the CAT is set, and based on the GHOST correction pattern data, a secondary exposure is performed on the sensitive substrate that has been subjected to the primary exposure. Proximity effect correction method. 4. The proximity effect correction method according to claim 3, wherein a reticle pattern shape is adjusted by dose adjustment when drawing and exposing the reticle for primary exposure. 5. The proximity effect correction method according to claim 3, wherein the shape of the reticle exposure pattern data is adjusted when the primary exposure reticle is subjected to the drawing exposure. 6. The proximity effect correction method according to claim 1, wherein the shape is corrected only for a pattern having a size of four times or less the blur amount of the charged particle beam applied to the sensitive substrate. . 7. The proximity effect correction method according to claim 2, wherein the dose correction is performed only for a pattern having a size of four times or less the blur amount of the charged particle beam irradiated on the sensitive substrate. 8. A reticle to which proximity effect correction has been applied by the method according to claim 3. Description: 9. A device manufacturing method, wherein a proximity effect correction is performed by the method according to claim 1 in a lithography step using a charged particle beam.