JPH0897122A - Charged particle beam projection method and apparatus - Google Patents

Abstract

(57) [Summary] [Object] In a charged particle beam irradiation apparatus using a stencil mask, a charged particle beam irradiation method for reducing the number of masks and partially varying the beam irradiation amount and a charged particle beam irradiation apparatus for realizing the method are provided. The purpose is to provide. A charged particle beam projection method of irradiating a stencil mask capable of transmitting charged particles with a charged particle beam and projecting a stencil mask pattern onto a sample by the charged particle beam transmitted through a stencil mask, comprising: The dose of the charged particle beam is changed depending on the pattern. [Effect] Since the pattern of the stencil mask can be projected onto the sample by partially changing the beam irradiation amount, it is possible to reduce the number of stencil masks and improve the processing throughput.
This has the effect of reducing the alignment error seen when using multiple masks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle beam projection method for performing fine processing by using a charged particle beam such as an electron beam or an ion beam, and a charged particle beam projection apparatus for realizing the method.

[0002]

2. Description of the Related Art A charged particle beam projection apparatus illuminates a stencil mask having a pattern of through holes and recesses provided in a charged particle optical system by using a charged particle beam such as an ion beam or an electron beam, and this pattern is illuminated. This is a device for projecting the passed charged particle beam on the sample after being magnified or reduced by a lens. This is an apparatus for processing a sample in a pattern on the stencil mask on the sample by utilizing physical or chemical changes caused in the sample by projecting a charged particle beam that has passed through the stencil mask.

As a conventional example of this type of charged particle beam projection apparatus, an ion projection type reduction exposure apparatus or a cell projection type electron beam exposure apparatus which projects (exposes) a reduction pattern of a stencil mask onto a sample with an ion beam or an electron beam. and so on.

The details of the ion projection type reduction exposure apparatus are described in "Microelectronic Engineering", Vol. 17, (1992), pp. 229-240.
(Microelectronic Engineering, 17 (1992) 229-240), A. Chalupka et al. Described “Progress in Ion Projection Lithography (P.
rogress in ion projection lithography) ”(known example 1). FIG. 2 shows a schematic configuration of the ion projection type reduction exposure apparatus 20. A stencil mask 23 having an opening pattern is collectively irradiated with an ion beam 22 of a light element such as hydrogen or helium emitted from a duoplasmatron type ion source 21, and the ion beam 22 passing through the stencil mask 23 is lens 24. The sample 26 is focused and made into a parallel beam 29 by the projection lens 25.
By irradiating the wafer coated with the resist,
Ion exposure can be performed in a reduced view shape of the opening pattern of the stencil mask 23. The stencil mask 23 is coated on the mask stage 27, and the surface of the sample 26 is coated with a resist. The apparatus is said to have the effect of exposing a fine structure with less blur compared to a conventional reduction projection apparatus using light.

Further, as a publicly known example of the electron beam, B8, (1990) of the collection of papers, "Journal of Vacuum Science and Technology",
1836 to 1840 (Journal of Vacuum Sc
ience and Technology, B8 (1990) 1836-1840), Nakayama et al. (Electron-beam cell pr
ojection lithography: A new high-throughput electr
on-beam direct-writing technology using a specially
A projection electron beam lithographic apparatus is shown in a paper entitled "Tailored Si aperture" (known example 2). This is, as shown in FIG. 3, an electron gun 31, a stencil mask 32, two-stage irradiation magnetic field lenses 34 and 34 ',
Scanning deflector 35 'and one-stage projection magnetic field lens 34''
The sample table 38 on which the sample 37 is installed has a basic configuration. A plurality of types of patterns 36 are set on the stencil mask 32, and an electron beam 3 is formed on the pattern by the deflector 35 in the upper stage.
9 is applied to form a pattern, and the pattern is transferred to the sample 37.

[0006]

The conventional charged particle beam device has the following problems.

(B) Correspondence to change in charged particle beam projection amount Focusing on ions as an example of charged particles, there is a conventional need for partially changing the ion projected amount within one pattern area on a stencil mask. In this device, multiple dedicated stencil masks are required for each difference in ion implantation amount, which cannot be easily realized from the viewpoints of mask alignment accuracy when replacing the stencil mask, throughput, and manufacturing cost of the stencil mask itself. It was This is shown in FIG.
Will be explained.

FIG. 4A shows a desired ion projection area. Here, when it is desired to make a difference in the ion projection amount to the region 40 and the region 41, in the above-mentioned conventional apparatus, the stencil mask 42 having the pattern for the ion projection region 40 shown in FIGS. A stencil mask 43 having a pattern for the projection area 41 is required, and the stencil masks 42, 43 are used to project a desired ion projection amount corresponding to each area 40, 41 by exchanging the stencil mask. In this example, since there are two types of regions having different ion projection amounts, the number of stencil masks is two. However, for example, ten types require ten stencil masks.

The cell projection electron beam exposure apparatus, which is a conventional example of the same type of charged particle beam apparatus, has the following problems.

(B) Pattern blurring due to proximity effect As shown in FIG. 5, the region of the sample surface where the resist is desired to be exposed is from the elongated regions 51 and 51 'which are very close to the large regions 50 and 50'. It is configured. When such a pattern is exposed by a conventional electron beam lithography apparatus, since the electrons are scattered in the resist, the areas 51 and 51 'contact each other in the reduced pattern after exposure, and an accurate elongated groove cannot be formed. This is the so-called proximity effect. In order to avoid this, the mask 52 provided with the patterns 53 and 53 ′ for the regions 50 and 50 ′ shown in FIG. 5B and the region 5 of FIG.
When the stencil mask 54 provided with the patterns 55 and 55 'for 1, 51' is prepared and the regions 51 and 51 'are exposed, the amount of projected electrons is reduced to reduce the proximity effect. In this example, at least two stencil masks are needed. Thus, in order to avoid the proximity effect, it is often the case that a plurality of stencil masks are required for beam irradiation to the same region.

In order to accurately project the charged particle beam using these plural stencil masks, the stencil masks must be replaced accurately. That is,
The accuracy of stencil mask alignment is the minimum requirement for forming the desired area. On the other hand, from the viewpoint of improving the number of final products produced per unit time (throughput), processing by beam projection (exposure and ion implantation)
It is required to shorten the time required for. Therefore, on the scale of throughput, the work requiring the replacement of many stencil masks, which requires the alignment time, was completely unfavorable. A charged particle beam projection method that can reduce the proximity effect without replacing multiple stencil masks,
A beam projection method in which the projection amount differs depending on the pattern has been desired.

In view of the above-mentioned problems, the first object of the present invention is to set the number of stencil masks to be used in a charged particle beam method for projecting an aperture pattern on a stencil mask onto a sample. Reduce,
It is an object of the present invention to provide a charged particle beam projection method in which a dose of a charged particle beam applied to a stencil mask can be distributed depending on locations in the mask. A second object of the present invention is to provide a charged particle beam projection apparatus which realizes the charged particle beam projection method of the first object.

[0013]

The first object is solved by a charged particle beam projection method capable of partially changing the amount of charged particle beam projection onto a sample. In particular,
(1) A charged particle beam is irradiated onto a stencil mask having a pattern of through holes or recesses through which charged particles can pass, and the reduced pattern of the stencil mask is projected onto a sample by the charged particle beam that has passed through the stencil mask. In the charged particle beam projection method, a charged particle beam projection method for changing the irradiation amount of the charged particle beam to the stencil mask according to the pattern, or
(2) A stencil mask having a pattern of through holes or recesses through which charged particles can pass is irradiated with a charged particle beam, and the reduced pattern of the stencil mask is projected onto a sample by the charged particle beam that has passed through the stencil mask. In the charged particle beam projection method, an area of the stencil mask irradiated with the charged particle beam is divided into small areas, and the irradiation amount of the charged particle beam is changed for each small divided area to reduce the stencil mask. Method for projecting a charged particle beam onto a sample, or
(3) A charged particle beam is applied to a stencil mask having a pattern of through-holes or recesses through which charged particles can be transmitted while scanning, and the reduced pattern of the stencil mask is applied to the sample by the charged particle beam that has passed through the stencil mask. A charged particle beam projection method for projecting the pattern of the stencil mask onto a sample by changing the irradiation amount of the charged particle beam to the stencil mask depending on the position in the stencil mask surface. Or (4) In the charged particle beam projection method according to (3) above, the method of changing the irradiation amount to the stencil mask depending on the position on the stencil mask surface is the number of beam scans, the scanning speed, and the stencil mask. Particles with at least one of the currents reached by Beam projection method, or (5) the charged particle beam projection method according to (3) above, which further comprises projecting the charged particle beam without the stencil mask, Or (6) irradiating a stencil mask having a pattern of through-holes or recesses through which charged particles can pass with a charged particle beam, and the reduced pattern of the stencil mask on the sample by the charged particle beam that has passed through the stencil mask. In the charged particle beam projection method of projecting, by limiting the irradiation location of the charged particle beam to the stencil mask, by changing the irradiation amount of the charged particle beam projected on the sample according to the projection location Will be realized.

Further, in the ion implantation method as these specific examples, (7) the charged particle beam in the charged particle beam projection method according to any one of (1) to (6) above is an ion beam, In the ion implantation method for implanting ions into the sample, or (8) in the ion implantation method according to (7) above, at least one of a dose of the ion beam projected onto the sample and an ion species is set at a projection location. Ion implantation method that changes according to
(9) In the ion implantation method according to any one of (7) and (8) above, a first ion species is implanted into the sample, and then a second ion species is deposited in a region other than the first ion implantation region. Ion implantation method for ion implantation, or (10)
The ion implantation method according to any one of (7) and (8) above, which is achieved by implanting a first ion species into the sample and then implanting a second ion species into the same place. It

Further, as a proximity effect in electron beam exposure as another specific example, (11) the charged particle beam in the charged particle beam projection method described in any one of (1) to (6) above is particularly an electron beam. An electron beam projection method for changing the irradiation amount of the electron beam projected on the sample according to a projection place, or (12) a proximity effect correction method in electron beam projection, comprising: (11)
This can be solved by a proximity effect correction method in which the electron beam irradiation method described is used to change the electron beam irradiation amount depending on the pattern and the pattern is projected onto a resist.

Further, the second object is (13) a charged particle source, a mask stage for holding a stencil mask having a pattern of through holes or recesses through which charged particles can pass, and a sample stage for holding a sample. A charged particle irradiation optical system for irradiating the stencil mask while extracting and scanning the charged particle beam from the charged particle source; and a reduced particle pattern of the stencil mask projected on the sample by the charged particle beam transmitted through the stencil mask. And a charged particle beam projection optical system for projecting the charged particle beam, wherein when the charged particle beam scans the stencil mask, a means for changing the beam irradiation amount for each position on the stencil mask is provided. Charged particle beam projection device or (14) Charged particle source and the transmission of charged particles A mask stage for holding a stencil mask having a pattern of through-holes or recesses, a sample stage for holding a sample, and irradiation optics of charged particles for irradiating the stencil mask while extracting and scanning a charged particle beam from the charged particle source. A charged particle beam projection apparatus comprising: a system; and a charged particle projection optical system that projects a reduced pattern of the stencil mask onto the sample by a charged particle beam that has passed through the stencil mask. A charged particle beam projection device provided with a beam scanning means for arbitrarily changing a scanning region on the mask, or (15) a charged particle source and a stencil mask having a pattern of through holes or recesses through which charged particles can pass. A mask stage for holding, a sample stage for holding a sample, A charged particle irradiation optical system for irradiating the stencil mask with a charged particle beam extracted from a charged particle source, and a charged particle for projecting a reduced pattern of the stencil mask onto the sample by the charged particle beam transmitted through the stencil mask. In a charged particle beam projection apparatus having a projection optical system of
A charged particle beam projection apparatus including a beam limiting means having a variable aperture between the charged particle source and the stencil mask,
Or (16) an ion beam projection apparatus in which the charged particle source in the charged particle beam projection apparatus according to any one of (13) to (15) is an ion source, or
(17) In the ion beam projector according to (15), the charged particles are particularly ions, and an ion beam projector provided with a mass separator between the charged particle source and the stencil mask, or (18) The charged particle beam source in the charged particle beam projector according to any one of (13) to (15) is realized by an electron beam projector that is an electron source.

[0017]

First, a charged particle beam projection apparatus which is an example of the present invention will be described with reference to FIG. The charged particles used here are ions, and the charged particle beam projection apparatus of FIG. 6 is specifically an ion implantation apparatus that does not require a resist on the sample surface.

In the ion implanter 61, an ion source was used as an example of a charged particle source. An ion beam 63 extracted from an ion source 62 (a liquid metal ion source that emits boron ions in this example) is irradiated onto a stencil mask 65 by an irradiation optical system 64. (Accelerating voltage 10 kV)
The stencil mask 65 is held on the mask stage 66. The stencil mask 65 is provided with through holes composed of a fine pattern and a rough pattern (for example, 90 and 91 are rough patterns in FIG. 7B, 92 is a fine pattern). The ion beam 63 that has passed through the stencil mask 65 is projected onto the sample 6 by the projection optical system 67.
8 is irradiated. Actually, the openings 90 ′, 91 ′, and 92 ′ are reduced and projected as one block. The projection optical system 67 transfers a large number of images of this pattern block onto the sample 68.
The reduction ratio of this embodiment is set to 1/8. The sample 68 is held by the sample stage 69 and can move in a horizontal plane.

The irradiation optical system 64 includes an irradiation lens 70 (three-electrode electrostatic lens), a lens 71 (three-electrode electrostatic lens), a beam limiting aperture 72, an E × B mass separator 73. Alignment deflector 74, blanking deflector 75 (two-pole electrostatic deflector), and blanking aperture 7
6 and a scanning deflector 77. Lens 71
Draws out the ion beam 63 with a necessary and sufficient intensity to form a crossover 78 of the ion beam 63. Unwanted ions distant from the central axis of the ion beam 63 are limited by the beam limiting aperture 72. The ion beam 63 is moved to the blanking aperture 7 by the blanking deflector 75.
It is shielded from the sample 68 by being deflected on 6.
Further, the unnecessary ion species component of the ion beam 63 is E
It is shielded from the sample 68 by being deflected by the × B mass separator 73 on the blanking aperture 76 which also serves as the mass separation aperture. The E × B mass separator 73 has a crossover 78 of the ion beam arranged at the center thereof to suppress the occurrence of chromatic aberration. The alignment deflector 74 deflects the ion beam 63 to generate the ion beam 6
The axis of 3 passes through the central axes of the irradiation lens 70 and the projection lens 79. The mass separator, the blanking deflector, and the blanking aperture are provided in the irradiation optical system 64 in order to suppress the deterioration of the stencil mask 65 due to the irradiation of the ion beam 63. Even if it is provided in 67, the operation does not change. The irradiation lens 70 is arranged so as to form an image of the ion source at a magnification of about 1 time.
The mask 55 is irradiated while converging No. 3. The distance between the center of the irradiation lens 70 and the ion source is about 700 mm.

The projection optical system 67 includes a projection lens 79 (electrostatic lens with three electrodes), a beam limiting aperture 80, a rotation corrector 81 (electromagnetic coil), and a position correction deflector 82.
The position correction deflector 82, which is composed of (8-pole electrostatic deflector), deflects the ion beam 63 that has passed through the stencil mask 65 onto the sample 68, and thereby the image position of the stencil mask 65 on the sample 68. Correct the gap. The beam limiting aperture 80 removes the ion beam scattered in the apparatus. The rotation corrector 81 is an electromagnetic lens whose lens strength is negligible, and rotates the ion beam 63 transmitted through the stencil mask 65 to correct the image rotation of the stencil mask 65 on the sample 68. The projection lens 70 uses the ion beam 6
In order to accelerate 3 from 10 kV to 20 kV, the voltage across it is asymmetric.

The first feature of this apparatus is that the projection optical system 67 is provided with only one projection lens 79 (electrostatic lens with three electrodes) and the irradiation optical system 64 is provided with the irradiation lens 70.
Ion beam 63
Is focused on the approximate center of the projection lens 79. As a result, the image distortion less than the 9th order of the lens aperture ratio is eliminated on the sample, and a sharp image is obtained.

The second feature is that the ion beam 63 is scanned on the stencil mask 65 by the scanning deflection system 77 having the deflection center at the crossover 78 of the ion beam 63. As a result, the ion irradiation distribution on the stencil mask 65 can be made uniform without being affected by the intensity distribution of the ion beam 2. The scanning deflection system 77 is composed of a main scanning deflector 77a (8-pole electrostatic deflector) and a sub-scanning deflector 77b (8-pole electrostatic deflector) that also serve as a ratio corrector, and their combined deflection centers are crossed. The deflection intensity ratio is set so as to be over 78. If the E × B mass separator 73 is not provided, the scanning deflector may be arranged in one stage and the center thereof may be installed at the crossover 78.

In order to achieve the above object by using the apparatus as described above, when the charged particle beam scans and irradiates the stencil mask, the charged particles partially form a dose distribution on the stencil mask. It can be realized by the beam projection method. In FIG. 6, a deflector 77 is means for scanning the stencil mask 65 with the charged particle beam 63. The method of deflecting the charged particle beam on the mask is not to make the irradiation amount (current amount) constant over the entire surface of one block, but to make the stencil mask correspond to the place to be irradiated on the sample and the ion implantation amount. The irradiation amount of the charged particle beam to the target is changed. The voltage (scanning deflection area) of the scanning power supply connected to the deflector, the number of times of scanning, the scanning speed, etc. are controlled by a computer (not shown), and the irradiation area and the irradiation amount on the mask can be controlled. Thus, it is possible to partially form the ion-implanted regions having different implantation amounts with respect to the pattern of one block.

[0024]

【Example】

(Embodiment 1) An example of performing ion implantation using the above apparatus (FIG. 6) will be described. The desired ion implantation area is shown in FIG.
And three types of regions 90 and 91 having different sizes.
And 92. The region 90 is 24 × 8 μm, the region 91 is 4 × 4 μm, and the region 92 is a square having a side of 2 μm. The ion species to be implanted is boron, and the ion implantation amount is 2 × 10 ¹³ / cm ^{2 in} the opening 90 and 2 × 1 in the opening 91.
0 ¹² pieces / cm ² , and the opening 92 has 8 × 10 ¹² pieces / cm ² .

FIG. 7B shows an opening pattern 90 ', 91' and 9 provided on the stencil mask 93 and corresponding to the ion implantation regions 90, 91 and 92 of FIG. 7A.
2 '. Aperture patterns 90 ', 91' and 92 '
Is substantially similar to the regions 90, 91 and 92. Since the mask shape is reduced during ion beam projection, the pattern size of the stencil mask is larger than the ion beam projection size. In this embodiment, since the reduction ratio is 1/8, the pattern size is 8 times the beam projection size. The stencil mask 93 is formed of a silicon plate, and its surface is coated with a metal film so that charge-up does not occur.

The ion implantation method will be described with reference to FIG.
FIG. 1 is a diagram showing a beam scanning method on a stencil mask. The beam scanning region is divided into regions by the opening patterns 1, 2, and 3 as shown in FIG. 1. Here, the regions are named A, B, C, and C ′ as shown in the figure, corresponding to the implantation dose.
The ion beam 5 scans from the upper left corner (C (0,0)) of the mask area to the right end (C (n, 0)) in the x direction, and blanks,
The scanning is performed again from the left (C (1,0)) to the right by shifting to the left end. This scanning is repeated up to C (n, m) to perform ion irradiation on the entire surface of the region C. At this time, the beam diameter was set to about 50 nm and the current density was set to 8 A / cm ² , the ion implantation amount was determined from the amount of current flowing into the sample and the irradiation time, and the beam scanning was repeated until the prescribed ion implantation amount was reached. . After the ion implantation to the C region is completed, the beam is moved to A (0,0) and the beam diameter is adjusted to 1 μm, and the wide region is quickly changed from A (0,0) to A (n, p).
Scanned. That the beam current density was reduced,
Since the desired ion implantation region has a lower concentration than the region C, the area of the region A is large, but the desired ion implantation is completed in a short time. Further, with respect to the region B and the lowermost region C ′, the beam diameter and the scanning speed are changed to perform a desired amount of ion implantation in each region.

Without this method, areas A, B, C,
While three masks corresponding to C ′ must be used separately for ion implantation, this method can be realized with only one mask. As a result, the mask replacement time and the alignment time at the time of using each mask are reduced, and the reduction in the number of masks brings about a great economic effect of reducing the time and cost involved in mask production.

As the beam scanning method, after the region C is ion-implanted, the beam position is changed to C (n, m) without changing the beam conditions.
From C ′ (0,0) to C ′ (0,0) at a high speed, and using the method of implanting ions into the region C ′, the effect of saving the time for setting the beam condition can be obtained.

(Embodiment 2) Here, an embodiment of an ion implantation method and apparatus using a charged particle beam projection apparatus having a configuration different from that of FIG. 6 for the pattern shown in FIG. 7 will be described. FIG. 7 is a schematic configuration diagram of the projection type ion implantation apparatus 100, which includes an ion source 101, an irradiation lens 103, and a stencil mask 10.
5, a projection lens 106 and the like. Ion source 1
Ion beam 102 emitted from 01 is irradiation lens 10
3 into a parallel beam and stencil mask 105
Is adjusted so that it is incident almost vertically on. The feature of this apparatus is that the variable slit 104 is installed immediately before the stencil mask. When the variable slit 104 is in the fully open state 104 ′, the stencil mask 105 is irradiated with all the ion beams 106 that have passed through the irradiation lens 103. Further, when the opening of the variable slit 104 is partially restricted 104 ″,
The passing beam becomes the limited beam 106, which can limit the area irradiated with the stencil mask 105. The ion beam whose irradiation area is limited irradiates a part of the stencil mask 105, passes through the pattern provided on the stencil mask 107, and is reduced by the projection lens 108.
The pattern reduced by the objective lens 109 is the sample 1
Vertical incidence on 10 is possible.

A method of implanting ions in the pattern of FIG. 7A using this apparatus will be described. FIG. 9 is a view showing the variable slit and the stencil mask portion in FIG. 8 in an easy-to-understand manner. The irradiation beam 130 is a variable slit 104A,
Limited by the opening 131 made by 104B, towards the mask 107. The stencil mask 107 has an opening pattern region 132 in which patterns are densely formed, and in the present embodiment, it is composed of two kinds of opening pattern rows 133 and opening pattern rows 134. In FIG. The shaped beam 106 is being irradiated. The shaped irradiation beam 106 passes through the aperture pattern row 133 and becomes a row of projection beams 135 corresponding to the openings. By performing projection for a predetermined time on the sample in this state, predetermined ion implantation into the opening pattern 133 is completed. Next, the variable slit 104 quickly
Operate A and 104B, and the shaped beam is opening pattern row 1
By moving and adjusting so as to irradiate 34, a predetermined ion can be implanted into the opening pattern 134.
Of course, if the amount of ion implantation into the opening pattern rows 133 and 134 is different, it is only necessary to adjust the projection time for each. Therefore, the amount of ion implantation can be changed depending on the pattern with one mask. Further, in this method, the irradiation beam 130 does not need to be deflected, and the mask 13 can be operated only by operating the variable slits 104A and 104B.
Beams can be selectively emitted to the openings above the two.

In the present embodiment, ion implantation is used as an example, and an ion beam is used as an example of a charged particle beam.
This method can also be applied to electron beam lithography, and the exposure dose to the resist can be partially different.

FIG. 10 shows an example in which a mass separator is added to the ion beam projection apparatus of FIG. In FIG. 10, 140
Is an E × B mass separator that uses an electric field and a magnetic field.
Reference numeral 1 is a focusing lens, and 144 is a mass separation aperture. The ion source 101 can emit two types of dopant ions.
Ions emitted from the ion source 101 are passed through the E × B mass separator 140 to form dopant ions 143 and dopant ions 1
The orbit of 44 is changed, and the mass separation aperture 144 separates the ion beam 102 that passes through the downstream ion optical system and the ion beam that does not pass through it. At this time, the focusing lens 141 between the aperture and the mass separator focused the emitted ions 143 and 144 onto the mass separation aperture 144 to facilitate the separation of the ion beam. Further, the operations of the mass separator 140 and the variable aperture 104 are coordinated by the control device 145, and if a certain pattern A (not shown) on the mask 107 is irradiated with the dopant ions 143, the control device 145 controls the mass. Separator 1
Dopant ion 1 by adjusting the electric or magnetic field of 40
The opening position and the opening amount of the variable aperture 107 are controlled so that 43 passes through the aperture 144 and the variable aperture 104 can irradiate a predetermined pattern A on the mask 107. As a result, the ion species can be switched and the ion implantation location (the ion irradiation location on the mask) can be switched, and the ion beam projection time can be controlled to quickly control the ion implantation amount without replacing the mask.

(Embodiment 3) Next, an example of lithography using an electron beam as a charged particle beam will be described. FIG. 5 shows an example of the pattern shape on the mask. In this embodiment, FIG.
As shown in FIG. 5A, the opening 5 shown in FIGS.
A stencil mask with 3, 53 ', 55, 55' was used. A method of mounting this stencil mask on an electron beam projection apparatus of the type which scans a beam on a stencil mask based on the charged particle beam projection apparatus of FIG. 6 and exposes the resist with an electron beam will be described.

As shown in FIG. 11B, the electron beam is scanned and swept in the xy directions on the stencil mask 56. (57
Indicates a beam position, and 58 indicates a beam scanning direction. )
The electron beam irradiation amount per unit area at the openings 55 and 55 'was set to 80% at the openings 53 and 53'. First, the opening 53 is irradiated, the beam scanning and sweeping at the openings 55 and 55 ′ is completed, and when moving to the opening 53 ′, the irradiation amount at the opening 53 is returned to the same. By such an irradiation method, as shown in FIG.
Between areas 50 and 51, 51 and 51 ', 51' and 5
The contact in the exposed area due to the proximity effect observed between 0'was eliminated, and the desired shape could be exposed.

The electron beam scanning and sweeping method on the stencil mask 56 is not limited to the one described above, and the openings 53, 55, and 5 may be used.
After irradiating 5 ′ and 53 ′ evenly with a low dose, the opening 5
It is also possible to irradiate only 3, 53 'again.

Further, as another example of the optical system of the electron beam projection apparatus, an example of an electron beam projection apparatus based on the optical system shown in FIG. 8 in which a pattern on a stencil mask is collectively irradiated with a beam is shown. . The shape of the stencil mask used is shown in FIG.

First, as the first electron beam projection step, the opening patterns 53, 55, 5 on the stencil mask 56 are formed.
The entire 5'and 53 'are irradiated with an electron beam at a low dose. Next, in the second electron beam projection step, the region where the electron beam is irradiated on the stencil mask is limited to the opening 53 by the beam limiting variable aperture provided on the upper stage of the stencil mask, and then only the opening 53 ′ is irradiated. To do.
With this irradiation method, the openings 53, 53 ′ are formed on the sample surface.
The region corresponding to (1) was irradiated with a sufficient electron beam, and the minute regions 51 and 51 ′ were exposed with a small irradiation amount and without showing the proximity effect.

According to this method, the proximity effect can be reduced and the number of stencil masks can be reduced to one. The fact that only one stencil mask is used not only has an economical effect by reducing the number of stencil masks, but also requires complicated processes that require time, such as alignment between masks, which are observed when using a plurality of stencil masks. And the number of defective products that appear as a result can be reduced,
From these time effects and quality improvement aspects, a great economic effect was brought about comprehensively.

[0039]

According to the present invention, since the mask pattern can be projected by partially changing the irradiation conditions, the number of masks can be reduced, the throughput of processing can be improved, and the alignment error observed when using a plurality of masks. Has the effect of reducing.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a method of irradiating a charged particle beam according to the present invention, and particularly a diagram for explaining a method of scanning and sweeping a charged particle (ion) beam on a mask.

FIG. 2 is a diagram for explaining a schematic configuration of an ion projection type reduction exposure apparatus of a conventional apparatus.

FIG. 3 is a diagram for explaining a schematic configuration of an electron beam exposure apparatus of a conventional apparatus.

FIG. 4 is a view showing an ion implantation region when performing ion implantation with a conventional apparatus (a) and a diagram showing a corresponding mask shape (b).
It is (c).

FIG. 5 is an example of a pattern for performing electron beam lithography with a conventional apparatus. FIG. 7A is a diagram for explaining a desired pattern shape, and FIGS. 9B and 9C are diagrams for explaining a corresponding mask shape.

FIG. 6 is a schematic configuration diagram for explaining a configuration of a charged particle beam device.

7 (a) shows a region to be ion-implanted, and FIG. 7 (b) shows a case where the charged particle beam apparatus of FIG. 5 is used.
7 is a mask corresponding to.

FIG. 8 is a schematic configuration diagram of a charged particle beam device equipped with a variable slit used in a second embodiment.

FIG. 9 is a perspective view for explaining a state of a charged particle beam passing through a variable slit and a mask in the charged particle beam apparatus used in the second embodiment.

FIG. 10 is a schematic configuration diagram for explaining the configuration of a charged particle beam device equipped with a mass separator and a variable slit used in the second embodiment.

FIG. 11 (a) is a view for explaining the stencil mask used in the electron beam projection apparatus used in Example 3,
(B) is a diagram showing a beam scanning and sweeping method on the stencil mask.

[Explanation of symbols]

1, 2, 3, 4 ... Ion implantation area (aperture), 5 ... Beam position, A, B, C, C '... Beam irradiation area, 21, 6
2, 101 ... Ion source, 22, 63 ... Ion beam,
23, 42, 43, 52, 54, 56, 65, 93, 1
07 ... Stencil mask, 24, 34, 34 ', 3
4 ″, 71, 103 ... Lens, 25 ... Projection lens,
26, 68, 110 ... Sample, 27, 66 ... Mask stage 28, 69 ... Sample stage. 30 ... Electron beam exposure apparatus 31 ... Electron gun 32 ... 1st lens 32 '... 2nd lens, 33 ... Electron beam, 35, 35' ... Deflector, 36 ... Pattern, 37 ... Wafer 38 ... Exposure area. 40, 41 ... Ion implantation regions 40 ′, 41 ′,
53, 53 ', 55, 55' ... Opening, 50, 50 ', 5
1, 51 '... Electron beam irradiation area. 61 ... Charged particle beam device, 64 ... Irradiation optical system, 67 ... Projection optical system, 7
0 ... Irradiation lens, 72 ... Beam limiting aperture, 7
3, 140 ... E × B mass separator, 74 ... Alignment deflector, 75 ... Blanking deflector, 76 ... Blanking aperture (mass separation aperture) 77 ... Scanning deflection system 78 ... Main scanning deflector, 79 ... Sub-scanning Deflector. 8
0 ... Limiting aperture, 81 ... Rotation corrector, 82 ... Position corrector, 90, 91, 92 ... Ion implantation area, 9
0 ', 91', 92 '... Opening. 102, 130 ... Irradiation beam, 104A, 104B ... Variable slit, 105 ...
Shaped beam, 106 ... Shaped beam, 108 ... Projection lens, 109 ... Objective lens. 131 ... Variable aperture, 132
... Aperture pattern area, 133 ... Aperture pattern row A, 1
34 ... Aperture pattern row B, 135 ... Projection beam, 14
1 ... Focusing lens, 142, 143 ... Dopant ion,
144 ... Mass separation aperture, 145 ... Control device.

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01J 37/305 B 9508-2G (72) Inventor Yuichi Masho 1280-chome, Higashi Koikeku, Kokubunji, Tokyo Hitachi, Ltd. Central Research Laboratory

Claims (20)

[Claims] 1. A stencil mask having a pattern of through-holes or recesses through which charged particles can pass is irradiated with a charged particle beam, and the reduced pattern of the stencil mask is projected onto a sample by the charged particle beam that has passed through the stencil mask. In the charged particle beam projection method for projecting, the irradiation amount of the charged particle beam onto the stencil mask is changed according to the pattern. 2. A stencil mask having a pattern of through holes or recesses through which charged particles can pass is irradiated with a charged particle beam, and the reduced pattern of the stencil mask is projected onto a sample by the charged particle beam that has passed through the stencil mask. In the charged particle beam projection method of projecting, the region on the stencil mask to be irradiated with the charged particle beam is divided into small regions, and the charged particle beam irradiation amount is changed for each of the small divided regions to obtain the stencil mask. A method for projecting a charged particle beam, which comprises projecting a reduced pattern on a sample. 3. A stencil mask having a pattern of through holes or recesses through which charged particles can be transmitted is irradiated with a charged particle beam while scanning, and the reduced pattern of the stencil mask is reduced by the charged particle beam that has passed through the stencil mask. In the charged particle beam projection method of projecting onto a sample, the irradiation amount of the charged particle beam onto the stencil mask is changed depending on the position within the stencil mask surface, and the pattern of the stencil mask is projected onto the sample. And a charged particle beam projection method. 4. The charged particle beam projection method according to claim 3, wherein the irradiation amount to the stencil mask is changed depending on the position in the stencil mask surface, the number of beam scannings, the scanning speed, and the amount of current reaching the mask. A charged particle beam projection method, comprising: 5. The charged particle beam projection method according to claim 3, further comprising projecting the charged particle beam with the stencil mask removed. 6. A stencil mask having a pattern of through-holes or recesses through which charged particles can pass is irradiated with a charged particle beam, and the reduced pattern of the stencil mask is projected onto a sample by the charged particle beam that has passed through the stencil mask. In the charged particle beam projection method of projecting, the irradiation location of the charged particle beam to the stencil mask is limited, and the irradiation amount of the charged particle beam projected onto the sample is changed according to the projection location. Particle beam projection method. 7. The charged particle beam projection method according to any one of claims 1 to 6, wherein the charged particle beam is an ion beam in particular, and ion implantation is performed on the sample by projecting the ion beam onto the sample. Ion implantation method. 8. The ion implantation method according to claim 7, wherein
An ion implantation method characterized in that at least one of an irradiation amount of the ion beam projected onto the sample and an ion species is changed according to a projection place. 9. The ion implantation method according to claim 7, wherein a first ion species is implanted into the sample, and then a second ion species is ionized except in the first ion implantation region. An ion implantation method characterized by implanting. 10. The ion implantation method according to claim 7, wherein the sample is implanted with the first ion species, and then the second ion species is ion-implanted at the same location. Ion implantation method. 11. The charged particle beam projection method according to claim 1, wherein the charged particle beam is an electron beam, and the irradiation amount of the electron beam projected onto the sample depends on the projection location. A method of projecting an electron beam, which is characterized in that 12. A proximity effect correction method in electron beam projection, wherein the electron beam irradiation method according to claim 10 is used to change an electron beam irradiation amount according to a pattern.
A proximity effect correction method comprising projecting the pattern onto a resist. 13. A charged particle source, a mask stage holding a stencil mask having a pattern of through holes or recesses through which charged particles can pass, a sample stage holding a sample, and a charged particle beam from the charged particle source. An irradiation optical system of charged particles for irradiating the stencil mask while pulling out and scanning, and a projection optical system of a charged particle beam for projecting a reduced pattern of the stencil mask on the sample by a charged particle beam transmitted through the stencil mask. In a charged particle beam projection apparatus provided with the charged particle beam projection apparatus, when the charged particle beam scans the stencil mask, there is provided means for changing a beam irradiation amount for each location on the stencil mask. . 14. A charged particle source, a mask stage for holding a stencil mask having a pattern of through holes or recesses through which charged particles can pass, a sample stage for holding a sample, and a charged particle beam from the charged particle source. An irradiation optical system for charged particles that irradiates the stencil mask while pulling out and scanning, and a charged particle projection optical system that projects a reduced pattern of the stencil mask onto the sample by a charged particle beam that has passed through the stencil mask. The charged particle beam projection apparatus according to claim 1, further comprising beam scanning means for arbitrarily changing an area to be scanned on the stencil mask by the charged particle beam. 15. A charged particle source, a mask stage holding a stencil mask having a pattern of penetrating holes or recesses through which charged particles can pass, a sample stage holding a sample, and charged particles extracted from the charged particle source. A charged particle irradiation optical system for irradiating the stencil mask with a beam, and a charged particle projection optical system for projecting a reduced pattern of the stencil mask onto the sample with a charged particle beam transmitted through the stencil mask. The charged particle beam projection apparatus according to claim 1, wherein the charged particle beam projection apparatus further comprises a beam limiting unit having a variable aperture between the charged particle source and the stencil mask. 16. An ion beam projection device according to claim 13, wherein the charged particle beam source in the charged particle beam projection device is an ion source. 17. The ion beam projection apparatus according to claim 16, further comprising a mass separator between the ion source and the stencil mask. 18. An electron beam projection apparatus according to claim 13, wherein the charged particle beam source in the charged particle beam projection apparatus is an electron source. 19. A semiconductor device manufactured by using the ion implantation method according to claim 7. 20. A semiconductor device manufactured by using the proximity effect correction method according to claim 12.