JP3388204B2 - Mask, exposure apparatus and electron beam size drift correction method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for transferring a fine pattern used in a manufacturing process of a semiconductor such as an MPU (ultra-compact processor) or a RAM (random write / read memory), and more particularly to a variable molding. The present invention relates to a mask, an exposure apparatus, and an electron beam size drift correction method that can perform size drift correction of a shaped beam in an electron beam writing system without reducing throughput.

[0002]

2. Description of the Related Art MPU (Ultra-compact processor) and RAM
An electron beam pattern forming method using variable shaping is known as one of fine pattern transfer techniques used in a manufacturing process of semiconductors typified by (random writing memory). The electron beam pattern forming method using such variable shaping has an upper stage first opening that defines the irradiation area of the electron beam and a lower stage that further shapes the electron beam that has passed through the first opening into a desired size. This is a technique for drawing by combining two of the second openings. However, there is a problem that the electron beam size slightly changes with time due to charge-up by the electron beam during drawing. Therefore, it is necessary to correct the electron beam size every stripe division of continuous drawing or every constant time.

A conventional dimension drift correction method will be described with reference to FIG. FIG. 5 is a schematic diagram of an apparatus for explaining ordinary electron beam drift correction. In FIG. 5, 41
Is an electron source, 41A is an electron beam, 41B and 41C are shaped beams, 42 is an upper mask having a first opening 42A for shaping the electron beam 41A from the electron source 41, 42A is a first opening, and 43 is a desired electron. A lower mask having a second opening 43A shaped into a beam size, 43A is a second opening, 44A is a deflector for shaking the electron beam that has passed through the first opening 42A, and 44B is an electron beam that has passed through the second opening 43A. A deflector for shaking, 45 is an electron detector for detecting reflected electrons emitted from the target pattern 48, 46 is a wafer placed on a wafer stage 47, 47 is a wafer stage, 48 is a target pattern, and 49B
Indicates the position directly below the electron beam. Referring to FIG. 5, in the conventional dimension drift correction method, first, the electron beam dimension calibration is first performed, and the shaped beam 41B that has passed through the first opening 42A is irradiated to a predetermined position of the second opening 43A and is kept constant. The shaped beam 41C having a size is formed, and then the target pattern 48 is irradiated while being deflected in one direction by the deflector 44B, and the reflected electrons passing through the target pattern 48 at this time are detected by the electron detector 45, and
Based on the detection result, the electron beam size of the shaped beam 41C is calibrated through the deflector 44A. In the next electron beam dimension calibration, after the wafer 46 is continuously drawn with a width of several mm (after execution of 1-stripe drawing), the wafer stage 47 is moved again so that the target pattern 48 comes to the position 49B immediately below the shaping beam 41C. Move and perform an electron beam size calibration similar to the first electron beam size calibration.
Thus, the electron beam dimension calibration was performed once each time one stripe was drawn.

[0004]

However, in the dimension drift correction method of the prior art, the electron beam dimension calibration is performed once each time one stripe is drawn, which is disadvantageous in terms of throughput. There is a second problem that the deviation of the electron beam size becomes large at the end of writing the stripe when the size drift is large.

The present invention has been made to solve the above problems, and a mask, an exposure apparatus, and an electronic device that can perform dimensional drift correction of a shaped beam in a variable shaped electron beam writing system without lowering the throughput. The purpose is to obtain a beam size drift correction method.

[0006]

[0007]

[0008]

[0009]

[0010]

A mask according to a first aspect of the present invention is a mask of a variable shaped electron beam drawing system.
The first shaped beam that passed through the upper mask
Furthermore, the second electron beam is formed into a desired electron beam size and the second forming beam is formed.
A second opening which is an opening for variable shaping for generating a chamber, and
By the first shaped beam that has passed through the upper mask,
Illuminated at the same time as the second opening for variable shaping
Has a third opening for detecting the electron beam drift.
And, wherein the electron beam second drift third opening is an opening for the detection is the numerical aperture of the variable shaping of the said second opening
It has an opening shape that spreads in a direction perpendicular to the opening.

A mask according to a second aspect of the present invention is a variable shaped electron beam drawing type mask,
The first shaped beam, which has passed through the step mask, is further subjected to a desired electric power.
Shape to a child beam size to generate a second shaped beam
A second opening, which is an opening for variable molding, and the upper mask
For the variable shaping by the first shaping beam that has passed
Beam that is illuminated at the same time as the second aperture
There is a third opening which is an opening for lift detection, and the third opening which is an opening for detecting the electron beam drift is perpendicular to a second opening which is an opening for variable shaping as the second opening. It has a narrow opening shape.

An exposure apparatus according to a third aspect of the present invention is a variable shaped electron beam drawing type exposure apparatus,
An electron source that generates and outputs an electron beam for exposure, an upper mask having a first opening that shapes the electron beam that has passed through the electron source to generate a first shaped beam, and the upper mask that has passed through the upper mask. The second shaped beam, which is an opening for variable shaping for shaping the first shaped beam into a desired electron beam size to generate a second shaped beam, and the first shaped beam that has passed through the upper mask It is an opening for detecting an electron beam drift that is illuminated at the same time as the second opening.
To spread in the direction perpendicular to the second opening, or
Is an opening shape narrowing in the direction perpendicular to the second opening.
The third mask having the third opening is separately provided in the X direction and the Y direction, and the lower mask arranged so that the third opening is partially irradiated by the first shaping beam, and the lower opening mask is passed through the first opening. First to change the orbit of the electron beam
A deflector, a second deflector for changing the trajectory of the electron beam passing through the second aperture, and a third deflector for the X and Y directions.
X-direction and Y-direction, which are respectively installed below the openings, and convert the beam amount of the shaped beam generated and output by the third aperture by the first shaped beam partially irradiating the third aperture into a current value. And a means for feeding back the amount of deflection of the first deflector in the X and Y directions in response to changes in the current values of the electron detectors in the X and Y directions, and the second molding device. A wafer stage on which the beam is irradiated.

[0013]

In the exposure apparatus according to the fourth aspect of the present invention, the third opening has an electron beam drift detection opening corresponding to the formation of a fine pattern.

[0015]

An electron beam dimension correcting method according to a fifth aspect of the present invention is an electron beam dimension correcting method for a shaped beam of a variable shaped electron beam drawing system, which is the first shaping by the first opening of the upper mask. When the second shaping beam is formed by irradiating the second shaping beam which is a variable shaping opening of the lower mask to shape the second shaping beam, the first shaping beam shaped by the first opening of the upper mask What opening der for electron beam drift detector for generating a shaped beam are simultaneously partially irradiated with the second opening by the
It extends in a direction perpendicular to the second opening, or the second
A third opening having an opening shape narrowing in the direction perpendicular to the opening is provided in each of the X direction and the Y direction, and
Current values of the shaped beam generated by the partially illuminated third aperture are measured by electron detectors in the X and Y directions, which are respectively installed below the third aperture in the Y direction and the Y direction, and the measurement is performed. The electron beam size is controlled by feeding back to the deflectors above the lower mask in the X and Y directions based on the change in the current value.

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The features of each of the following embodiments are that an electron beam dimension drift correction opening provided on a second opening and an electron beam dimension drift correction opening below the second opening are provided. Equipped with an electron detector installed, the amount of electron beam passing through the opening for electron beam dimension drift correction during pattern drawing is detected in real time by the electron detector, and the amount of current detected by the electron detector is detected. By performing feedback on the deflection amount to the deflector on the upper side according to the change, the drift of the electron beam dimension is corrected in real time at the time of exposure, so that the stable pattern dimension on the wafer surface can be obtained. Therefore, it is possible to improve the throughput. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1. Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is an apparatus schematic diagram for explaining an exposure apparatus that executes an electron beam size drift correction method using a mask according to an embodiment of the present invention. In FIG. 1, 1 is an electron source, 1A is an electron beam, 1B and 1C are shaped beams, 2 is an upper mask, 2A is an upper beam provided on an upper mask 2, and the shaped beam 1B is formed by shaping an electron beam 1A from an electron source 1. First aperture for generating (first shaped beam), 3 is a lower mask, 3A is provided on the lower mask 3, and shaped beam 1B (first shaped beam) is further shaped into a desired electron beam size and shaped beam A second aperture as a variable shaped aperture for generating 1C (second shaped beam), 3B is a third aperture as a variable shaped aperture that is attached to the second aperture 3A, and 4A is an electron beam that has passed through the first aperture 2A. For changing the trajectory of the electron beam, 4B for deflecting the trajectory of the electron beam passing through the second aperture 3A, 5 for an electron detector, 6 for a wafer, 7 for mounting a wafer 6 on a wafer. stage Shows.
Referring to FIG. 1, the exposure apparatus according to the present embodiment includes an electron source 1, an upper mask 2 having a first opening 2A, and a second opening 3A.
And a lower mask 3 having a third opening 3B, a deflector 4A (first deflector) and a deflector 4B for changing the orbit of electrons.
A wafer stage 7 that moves the wafer 6 on a two-dimensional plane (XY plane) for pattern drawing with the (second deflector), the electron detector 5, and the wafer 6 set.
It is composed mainly of.

Next, the operation of the exposure apparatus of FIG. 1 will be described with reference to the drawings.
(Electron beam dimension drift correction method)
It First, the electron beam 1A emitted from the electron source 1
Molded by passing through the first opening 2A provided on the step mask 2
Beam 1B (first shaped beam) is shaped and deflector 4 is formed.
A (first deflector) provided on the lower mask 3
Irradiation is performed on the second opening 3A and the third opening 3B. Second
A shaped beam 1C (second part) formed through the opening 3A.
Shaped beam) is deflected by the deflector 4B (second deflector).
It is deflected to a predetermined position on the wafer 6. At this time at the same time
The shaped beam 1C (the first beam formed through the three openings 3B)
2 shaped beam) to the electron detector 5 installed below.
The current value is measured according to the irradiation amount of the electron beam.
It In the present embodiment, the electron detector 5 is always used during drawing.
By monitoring the current value according to the electron beam irradiation amount,
Upper deflector according to changes in monitored current value4A
(FirstShaped beam 1 with feedback to the deflector)
Adjust the irradiation position of C (second shaped beam) on the wafer 6.
The electron beam size is always kept constant by adjusting
Running control.

FIG. 2 is a mask top view for explaining another embodiment of the mask according to the first embodiment of the present invention. In FIG. 2, 11B is a shaped beam that has passed through the opening of the upper mask 2 (shaped beam 1B (first shaped beam)), 13 is a lower mask, and 13A is a lower mask 13.
The shaped beam 11B (first shaped beam) is further shaped into a desired electron beam size and shaped beam 1C.
A second opening, which is an opening for variable shaping as the second opening 3A for generating (second shaping beam), and a third opening 3B provided side by side with the variable shaping opening 13A (second opening 3A).
An opening for electron beam drift detection as B is shown. Referring to FIG. 2, in the present embodiment, the variable molding opening 13A (second opening 3) on the lower mask 13 (3) is used.
Opening 13B for electron beam drift detection around A)
The (third opening 3B) is separately provided in the X direction and the Y direction, and the electron beam drift detection opening 13B (third opening 3B) is provided.
The electron detector 5 for detecting the shaped beam 1C (second shaped beam) that has passed through the aperture 3B is also characterized in that it is provided separately in the X direction and the Y direction.

Next, referring to the drawings, the lower mask 13 shown in FIG.
The operation of the exposure apparatus using (3) (electron beam dimension drift correction method) will be described. The electron beam drift detection opening 13B (third opening 3B) is provided adjacent to the variable shaping opening 13A (second opening 3A). Similarly, the forming beam 11B ( first forming bead surrounded by a broken line in the figure)
Beam) indicates the position of the shaped beam in forming the short fine pattern. Aperture 1 for electron beam drift detection
The position of 3B (third opening 3B) is arranged at a position that can correspond to fine patterns having different lengths. In the present embodiment, as shown in FIG. 2, a case is shown in which a fine line in the X direction is formed, but the problem here is the line width Y1 in the Y direction. Therefore, in the present embodiment, the aperture 1 for detecting the electron beam drift through which the shaped beam 11B (formed beam 1B (first shaped beam)) passes.
An electron detector 5 for detecting the above-mentioned Y shaped beam 1C (second shaped beam) installed below 3B (third opening 3B) is a deflector 4A (first deflector) installed above. ) Is configured to be linked to the control in the Y direction, and the opening 1 for detecting the electron beam drift not passing through
The electron detector 5 for detecting the above-mentioned X-shaped shaped beam 1C (second shaped beam) set below the 3B (third opening 3B) is arranged in the X-direction of the deflector 4A (first deflector). It is configured to coordinate with the control. In addition, electronic detector
5 constantly (or at constant time intervals) monitors (detects) the current value according to the electron beam irradiation amount, and the variation of the monitored current value is deflected by the deflector 4A (first deflection).
To a control means (not shown) of the electronic device to correct the deviation of the electron beam and to adjust the electron beam size Y1 in the Y direction.
Is configured to keep constant. The electron beam dimension drift correction method according to the present embodiment uses the variable shaped opening 13A (second opening 3) in the lower mask 13 (3).
A) The electron beam size is measured by using the electron beam drift detection aperture 13B (third aperture 3B) to perform electron beam size calibration.

As described above, according to the first embodiment, by correcting the electron beam size in real time, it becomes possible to form a stable pattern size within the plane of the wafer 6, and as a result, the throughput is improved. There is an effect that it becomes possible to.

Embodiment 2. Embodiment 2 of the present invention will be described below in detail with reference to the drawings. The same parts as those already described in the above embodiment are designated by the same reference numerals, and the duplicated description will be omitted. Figure 3
FIG. 6A is a mask top view for explaining a mask according to a second embodiment of the present invention. In FIG. 3, 21B is a shaped beam that has passed through the upper opening (shaped beam 1B).
(First shaping beam), 23 is an EB mask as the lower mask 3, 23A is a second opening which is a variable shaping opening as the second opening 3A, and 23B is an electron beam drift detection as the third opening 3B. The opening for is shown. Referring to FIG. 3, the present embodiment is characterized in that an electron beam drift detection aperture 23B (third aperture 3B) having a triangular pattern aperture shape is provided in the EB mask 23 (lower mask 3). Have

Next, based on the drawing, the EB mask 23 of FIG.
The operation of the exposure apparatus using the (lower mask 3) (electron beam dimension drift correction method) will be described. In FIG. 3, a shaped beam 21B (shaped beam 1B (first shaped beam)) surrounded by a broken line in the drawing indicates the position of the shaped beam when forming a short fine pattern. In Figure 3, X
Although the position of the shaped beam when forming a fine line in the direction is shown, it is the fine beam width Y2 in the Y direction that often causes a problem in a normal exposure process.
Therefore, in the present embodiment, the aperture 2 for detecting the electron beam drift through which the shaped beam 1B (first shaped beam) passes.
An electron detector 5 for detecting the above-mentioned Y shaped beam 1C (second shaped beam) installed below 3B (third opening 3B) is a deflector 4A (first deflector) installed above. ) And the opening 2 for detecting the electron beam drift which has not passed through.
The electron detector 5 for detecting the above-mentioned X-shaped shaped beam 1C (second shaped beam) set below the 3B (third opening 3B) is arranged in the X-direction of the deflector 4A (first deflector). It is configured to coordinate with the control. In addition, electronic detector
5 constantly (or at regular time intervals) monitors (detects) a current value according to the electron beam irradiation amount, and the fluctuation amount of the monitored current value is deflected by the deflector 4A (first deflection).
To a control means (not shown) of the electronic device to correct the deviation of the electron beam and to adjust the electron beam size Y1 in the Y direction.
Is configured to keep constant. The electron beam dimension drift correction method according to the present embodiment uses the variable-shaped opening 23A in the EB mask 23 (lower mask 3).
(Second aperture 3A), aperture 2 for detecting electron beam drift
Electron beam size calibration is performed by measuring the electron beam size using 3B (third opening 3B).

In the second embodiment, the opening shape of the electron beam drift detection opening 23B (third opening 3B) is a triangular pattern. However, the shape is not particularly limited to this, and an opening for variable shaping is also possible. The second opening 23A (second
There is no problem as long as it has an opening shape that is spread or pinched in the vertical direction of the opening 3A), and may be trapezoidal or polygonal.

As described above, in the present embodiment, the aperture shape of the electron beam drift detection aperture 23B (third aperture 3B) is made into a triangular pattern, so that the fine beam width Y is obtained.
Even when 2 is slightly changed, a large change in current value can be detected as compared with the first embodiment, and as a result, dimensional accuracy of about ± 5 nm can be achieved on the entire surface of the wafer 6. Further, by correcting the electron beam size in real time, it becomes possible to form a stable pattern size within the surface of the wafer 6, and as a result, it is possible to improve the throughput.

Embodiment 3. Hereinafter, a third embodiment of the present invention will be described in detail with reference to the drawings. The same parts as those already described in the above embodiment are designated by the same reference numerals, and the duplicated description will be omitted. Figure 4
[FIG. 8A] is a mask top view for explaining a mask according to a third embodiment of the present invention. In FIG. 4, 31B is a shaped beam (formed beam 1B (first shaped beam)) that has passed through the upper opening (first opening 2A of the upper mask 2), 33 is an EB mask as the lower mask 3, and 33
A is a second opening for variable molding as the second opening 3A
An opening, 33B is an opening for detecting an electron beam drift of a fine pattern width, and 33C is an opening for detecting an electron beam drift.

Referring to FIG. 4, in the present embodiment, a second opening 33A (second opening 3A) which is an opening for variable molding,
Aperture 33 for electron beam drift detection of fine pattern width
In addition to B (third opening 3B), an L-shaped electron beam drift detection opening 33C (fourth opening) is also set on the EB mask 33 (lower mask 3) at the same time. As a result, the electron beam length Y3 can be corrected at the same time as the electron beam dimension Y3, and as a result, dimensional accuracy of about ± 5 nm in the plane of the wafer 6 and stable shot joining can be realized. .
Further, by correcting the electron beam size in real time, it becomes possible to form a stable pattern size within the surface of the wafer 6, and as a result, it is possible to improve the throughput.

It should be noted that the present invention is not limited to the above-mentioned respective embodiments, and it is apparent that the respective embodiments can be appropriately modified within the scope of the technical idea of the present invention. Further, the number, positions, shapes, etc. of the above-mentioned constituent members are not limited to those in the above-mentioned embodiment, and the number, positions, shapes, etc. suitable for carrying out the present invention can be adopted. Moreover, in each figure, the same components are denoted by the same reference numerals.

[0035]

Since the present invention is configured as described above, it becomes possible to form a stable pattern dimension within the wafer surface by correcting the electron beam dimension in real time, and as a result, the throughput is improved. There is an effect that it becomes possible to do.

[Brief description of drawings]

FIG. 1 is an apparatus schematic diagram for explaining an exposure apparatus that executes an electron beam size drift correction method using a mask according to an embodiment of the present invention.

FIG. 2 is a mask top view for explaining another embodiment of the mask according to the first embodiment of the present invention.

FIG. 3 is a mask top view for explaining a mask according to a second embodiment of the present invention.

FIG. 4 is a mask top view for explaining a mask according to a third embodiment of the present invention.

FIG. 5 is an apparatus schematic diagram for explaining ordinary beam drift correction.

[Explanation of symbols]

1 electron source, 1A electron beam, 1B, 11B, 2
1B, 31B shaped beam, 1C shaped beam, 2
Upper mask, 2A First provided on upper mask
Opening, 3,13 Lower mask, 3A Second opening of lower mask, 3B Third opening of lower mask, 4A, 4
B deflector, 5 electron detectors, 6 wafers, 7
Wafer stage, 13A, 23A, 33A Variable molding opening (second opening), 13B, 23B, 33B
Aperture for electron beam drift detection (third aperture), 2
3, 33 EB mask (lower mask), 33 C Aperture for electron beam drift detection, 41 Electron source, 41
A electron beam, 41B, 41C shaped beam, 4
2 upper mask, 42A first opening, 43 lower mask, 43A second opening, 44A, 44B deflector, 45 electron detector, 46 wafer, 47
Wafer stage, 48 target patterns, 4
9B Position just below the shaped beam, X3 electron beam length,
Y1 shaped beam line width, Y2 fine beam width,
Y3 electron beam dimensions.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI H01J 37/147 H01L 21/30 541E

Claims (5)

(57) [Claims] 1. A variable shaped electron beam drawing type mask for variable shaping, wherein the first shaped beam that has passed through the upper mask is further shaped into a desired electron beam size to generate a second shaped beam. A second opening, which is an opening, and a third opening, which is an opening for electron beam drift detection, which is illuminated at the same time as the second opening, which is the opening for variable shaping, by the first shaping beam that has passed through the upper mask. A mask, wherein the third opening has an opening shape that extends in a direction perpendicular to the second opening. 2. A variable shaped electron beam drawing type mask for variable shaping, wherein the first shaped beam that has passed through the upper mask is further shaped into a desired electron beam size to generate a second shaped beam. A second opening, which is an opening, and a third opening, which is an opening for electron beam drift detection, which is illuminated at the same time as the second opening, which is the opening for variable shaping, by the first shaping beam that has passed through the upper mask. The third opening has an opening shape narrowed in a direction perpendicular to the second opening. 3. An exposure apparatus of a variable shaped electron beam writing system, comprising: an electron source for generating and outputting an electron beam for exposure; and an electron beam that has passed through the electron source to form a first shaped beam. An upper mask having a first aperture for generating, and a variable shaping aperture for further shaping the first shaped beam having passed through the upper mask into a desired electron beam size to produce a second shaped beam. 2 openings and the second beam by the first shaped beam that has passed through the upper mask.
Opening and I opening der for electron beam drift detector to be illuminated at the same time, extends in a direction perpendicular to the second opening
Or, an opening narrowing in a direction perpendicular to the second opening
A lower mask having a third opening having a shape separately in the X direction and the Y direction and arranged so that the third opening is partially irradiated by the first shaping beam; and the first opening. A first deflector for changing the trajectory of the electron beam that has passed, a second deflector for changing the trajectory of the electron beam that has passed through the second aperture, and a third deflector below the third aperture in the X and Y directions. Electron detectors in the X and Y directions, which are respectively installed and convert the beam amount of the shaped beam generated and output by the third aperture by the first shaped beam partially irradiating the third aperture into a current value. A means for feeding back the X-direction and Y-direction deflection amounts of the first deflector in response to changes in the current values of the electron detectors in the X-direction and the Y-direction, and the second shaped beam being irradiated. Wafer stage Exposure apparatus characterized by having. 4. The exposure apparatus according to claim 3, wherein the third opening is an opening for detecting an electron beam drift corresponding to the formation of a fine pattern. 5. A method of correcting an electron beam size of a shaped beam of a variable shaped electron beam drawing method, wherein the first shaped beam shaped by the first opening of the upper mask is an opening for variable shaping of the lower mask. When the second shaping beam is shaped by irradiating the second opening, the first shaping beam shaped by the first opening of the upper mask is partially illuminated at the same time as the second opening and shaped. What opening der for electron beam drift detector for generating a beam, a direction perpendicular to the second opening
Spread in the vertical direction or narrow in the direction perpendicular to the second opening.
The third openings having a round opening shape are provided in the X direction and the Y direction, respectively, and the partial detection is performed by the X-direction and Y-direction electron detectors installed below the third openings in the X-direction and the Y-direction, respectively. The current value of the shaped beam generated by the irradiated third opening is measured, and the electron beam is fed back to the deflectors above the lower mask in the X and Y directions based on the change in the measured current value. An electron beam size correction method characterized by controlling a size.