JPS5870529A - Charged beam optical lens-barrel - Google Patents

Abstract

PURPOSE:To eliminate the need for a lens forming crossover and to simply change the dimension and shape of beams by a method wherein one deflector of the two deflectors is positioned between each aperture mask and the other is positioned at a sample plane apart from each aperture mask or at an incident beam side. CONSTITUTION:An electron gun 11 is composed of a cathode 11a, a Wehnelt electrode 11b, and an anode 11c and crossover Q1 is formed at the vicinity of the upper part of a condenser lens 12 by an electron beam emitted from the electron gun 11. This crossover Q1 is magnified by the lens 12 and is imaged between the first and the second beam adjusting aperture masks 13, 14. A first deflector 15 is positioned between the masks 13, 14 and a second deflector 16 is positioned at the lower part of the mask 14. The dimension and shape of the beam are changed by the deflector 15 and the beam direction declined by the deflector 16 is set to an optical axis. The beam shaped by the deflectors 15, 16 is reduced by reduction and objective lenses 17, 18 to irradiate at a sample plane 19 and the structure of a device is simplified.

Description

Detailed Description of the Invention (1) Technical Field of the Invention The present invention relates to a charged beam source mirror wJK used in a charged beam exposure device such as an electron beam exposure device or an ion beam exposure device, especially a variable beam dimension. This invention relates to improvements in a charged beam optical column with functions.

(! PRIOR TECHNOLOGY Recently, various electron beam exposure devices have been developed to form fine patterns on samples such as semiconductor wafers and I-Series substrates. It is said that a so-called variable beam dimension type electron beam exposure apparatus, which performs writing while changing the shape, is most suitable for high-speed writing.

FIG. 1 is a schematic diagram showing the main parts of a conventional electron beam optical column used in such an apparatus. In the figure, 1 is a first aperture mask for beam shaping, 2 is a condenser lens, 3 is a deflector, and 4 is a second aperture mask for beam shaping. The first crossover P1 formed above the first aperture mask 1 is imaged at the deflection center of the deflector 3 from the lens JK, and the second crossover P1 is formed at this deflection center. The aperture of the first aperture mask 1 is projected by the lens 2 onto a second aperture mask 4, on which an aperture iron P is formed. When the electron beam is deflected in a predetermined direction by the deflector 3, the position of the aperture Ps with respect to the aperture of the second aperture mask 4 changes. That is, the overlapping state of the apertures of the second aperture mask 4 and the aperture iron Ps changes. This allows the second aperture mask 4 to be formed by a lens (not shown) or the like.
When the aperture of the second aperture 4 is imaged on the sample surface, the hoe that is finally imaged on the sample surface becomes a multi-part overlap between the aperture of the second aperture 4 and the aperture (11Ps). By deflecting the electron beam,
The advantage is that the size and shape of the beam irradiated onto the sample surface can be varied.

(3) Intermediate point of the conventional technology In the configuration shown in FIG. The beam intensity fluctuates. For this reason, the lens 2 for forming the crossover P at the deflection center of the deflector S becomes unstable, and this makes the configuration complicated, causing problems such as complicated adjustment and lack of stability. there were.

On the other hand, in order to solve the above problem, it is necessary to increase the depth of focus at the object point by increasing the reduction ratio of the lens system.The lens 2 is omitted and each aperture mask 1, as shown in FIG. A model in which two sets of deflections @5, r; are arranged between 4 and 4 has been announced (Hug'hes Res+
EARCH LAB). However, with this structure, if the distance between the two aperture masks 1.4 is widened, the beam will become blurred (resolution is poor), and if the distance is narrowed, the space for the two sets of deflectors will become smaller, making it difficult to manufacture them. There were drawbacks such as difficulty in Incidentally, the above-mentioned nine problems also apply to ion beam optical column.

(4) Purpose of the Invention The present invention has been made in consideration of the above circumstances, and its purpose is to improve the size and shape of the beam without requiring a lens for forming a crossover at the center of deflection of the deflector. We have developed a charged beam optical column that can simplify the device configuration, reduce costs, and improve stability, and that can shorten the distance between aperture masks and improve resolution. It is about providing.

(5) Summary of the Invention The present invention provides a charged beam optical lens barrel that uses two aperture masks and two sets of deflectors to vary the size and shape of a beam. and the other one is placed on the sample side or beam incidence side of each aperture mask.

(2) Since the lens between the two aperture masks is omitted by increasing the depth of focus at the effect object point of the invention, the device configuration can be simplified and costs can be reduced. Furthermore, since the lens is omitted, there is no need for axis alignment or other adjustments associated with this lens, and stability can be improved. Furthermore, since only one set of deflectors is required between the aperture masks, the distance between the aperture masks can be shortened, thereby greatly improving resolution.

(7) Examples of the invention Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 3 is a schematic configuration diagram showing an embodiment in which the present invention is applied to an electron beam exposure apparatus. 11 in the figure is the cathode Ila
, an electron gun consisting of a Quesnelt electrode 11b and an anode IIC, and an electron beam emitted from this electron gun 11 is passed through a crossover Q near the upper part of a condenser lens 12.
, form. Crossover Q1 is condenser lens 1
2 and is imaged at the center of the first and second beam shaping aperture masks 13 and 14. A first deflector z5 is arranged between the aperture masks 13 and 14, and a second deflector 16 is arranged below the second aperture mask Z4. The first deflector I5 changes the size and shape of the beam depending on the relationship with each aperture of the aperture mask 1jtI4, and the second deflector 16 is the first deflector.

This is for aligning the direction of the beam tilted by I5 with the optical axis. The beam shaped through the aperture mask Is, 14 and the deflector 15, 16 is reduced by the lower reduction lens 11 and objective lens 18, and imaged onto the sample surface 19. In this way, the sample surface 19 is irradiated with a shaped beam.

With such a configuration, the first deflector 15 deflects the beam by a predetermined amount, and the second deflector 16 returns the deflected beam (SF) to the sample fJ19. The size and shape of the beam can be variably controlled. And in this case, two aperture masks 13.14
There is no need to provide a lens between the two, making it possible to simplify the configuration, reduce costs, and improve stability. Further, the distance between the aperture masks 13 and 14 may be such that only the first deflector 15 can be disposed, and two sets of aperture masks can be biased. This has the effect of improving the degree of resolution. By the way, if the reduction ratio by the lens 17.18 is 1/100, the distance between the aperture masks 13.14 may be about 20 [degrees], and this distance is sufficient to arrange the first deflector I5. , and it was within a range that had almost no effect on resolution.

(8) Modifications of the Invention The present invention is not limited to the embodiments described above, and can be implemented with various modifications without departing from the spirit thereof. For example, the second deflector may be arranged above the first aperture mask. Furthermore, the deflector may utilize either electrostatic deflection or electromagnetic deflection. Further, in the embodiment, a case where the present invention is applied to an electron beam exposure apparatus has been described, but the present invention can also be applied to an ion beam exposure apparatus. Furthermore, the present invention is applicable not only to exposure apparatuses but also to various charged beam apparatuses that require variable beam dimensions, shapes, etc.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic diagrams showing the main parts of a conventional electron beam optical column, respectively, and FIG. 3 is a schematic diagram showing an embodiment in which the present invention is applied to an electron beam exposure apparatus. 11... Electron gun, 12... Condenser lens, 13
．． 14... Aperture mask for beam shaping, 15.1
6... Deflector, 11... Reduction lens, 18. Pair i
Lens, 19...sample surface.

Claims (1)

[Claims] In a charged beam optical column that includes two aperture masks and two sets of deflectors arranged to face each other and variably controls the size or shape of a charged beam and irradiates the beam onto a sample surface, the above-mentioned 2. A charged bee five-party mirror characterized in that one of the set of deflectors is disposed between each of the aperture masks, and the other is disposed on the sample surface side or beam incidence side of each of the seven aperture masks. Simple.