Radiant energy – Irradiation of objects or material – Irradiation of semiconductor devices
Reexamination Certificate
2003-04-04
2004-11-16
Lee, John R. (Department: 2881)
Radiant energy
Irradiation of objects or material
Irradiation of semiconductor devices
C250S3960ML, C250S441110
Reexamination Certificate
active
06818911
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an array structure and method of manufacturing the same, a charged particle beam exposure apparatus, and a device manufacturing method and, more particularly, to an array structure which can suitably be used as a blanking aperture array of a charged particle beam exposure apparatus, a method of manufacturing the array structure, a charged particle beam exposure apparatus having the array structure as a blanking aperture array, and a device manufacturing method using the charged particle beam exposure apparatus.
BACKGROUND OF THE INVENTION
A multiple charged particle beam exposure apparatus using a plurality of charged particle beams employs a method of individually controlling irradiation of the plurality of charged particle beams using a blanking aperture array having a plurality of openings (e.g., Utility Model Publication No. 56-19402).
Generally, a blanking aperture array is manufactured by two-dimensionally forming a plurality of openings in a semiconductor crystal substrate made of, e.g., silicon at a predetermined interval and forming a pair of blanking electrodes on both sides of each opening. When voltage application
on-application to each pair of blanking electrodes is controlled in accordance with pattern data, a desired pattern can be formed on a sample.
For example, when one of the pair of blanking electrodes formed in correspondence with each opening is grounded, and a predetermined voltage is applied to the other blanking electrode, an electron beam passing through the opening is deflected. Since the electron beam passes through a lens arranged on the lower side and is then shielded by a single-opening aperture, the beam does not reach the sample surface (a resist layer on the semiconductor substrate). On the other hand, if no voltage is applied to the other electrode, the electron beam passing through the opening is not deflected. Hence, the electron beam passes through the lens arranged on the lower side and reaches the sample surface without being shielded by the single-opening aperture.
The blanking electrode of the blanking aperture array is typically made of a metal. A conventional blanking electrode forming method will be described with reference to
FIGS. 19A and 19B
.
FIG. 19A
shows only one of a plurality of pairs of blanking electrodes.
FIG. 19B
shows only one of the pair of blanking electrodes. First, as shown in
FIG. 19A
, a pair of trenches are formed in a substrate
41
. An insulating film
42
is formed to cover the trench surfaces and substrate surface. A metal (e.g., tungsten) is deposited in the trenches by vapor deposition or sputtering to form a pair of metal electrodes
43
. The substrate portion between the pair of metal electrodes
43
is removed by etching to form an opening. The insulating films on side surfaces of the opening are removed by etching.
In the conventional metal electrode forming method, since the depth of the trench is large relative to its width. Hence, as shown in
FIG. 19B
, in forming the insulating film
42
on the trench surface, the insulating film
42
may not uniformly be formed on the trench surface. In this case, the uncovered substrate
41
may electrically short-circuit to the metal electrode
43
.
If the substrate
41
and metal electrode
43
electrically short-circuit, no predetermined voltage can be applied to the metal electrode
43
. Accordingly, since the electron beam cannot appropriately be deflected, no desired pattern can be formed on a sample.
Additionally, even when the substrate
41
and metal electrode
43
do not short-circuit yet in manufacturing, they may short-circuit during use of the exposure apparatus due to, e.g., degradation at the thin portion of the insulating film
42
.
Furthermore, in the conventional blanking electrode forming method, when the metal is deposited in the trench (the trench is filled with the metal), a void (cavity) is formed at the center of the trench, as shown in
FIGS. 5A and 5B
. It is therefore difficult to completely fill the trench.
More specifically, in the conventional forming method, a trench is formed in, e.g., a silicon substrate
51
by selective etching (trench etching). An SiO
2
insulating film
52
is formed on the entire surface of the substrate
51
, including the trench. Tungsten
53
as a prospective blanking electrode is deposited by sputtering. At this time, since the entire underlying layer of the tungsten
53
is made of the insulating film
52
, the trench cannot be filled with the metal using selective growth, and a void
54
may be formed, as shown in FIG.
5
B.
With such a void formed in a blanking electrode, when an opening is formed between a pair of blanking electrodes, and the insulating films
52
on the side surfaces of the opening are removed, the blanking electrode may partially break. Even when the blanking electrode does not break during manufacturing the blanking aperture array, the blanking electrode may be deformed by heat applied to it during use of the exposure apparatus having the blanking aperture array. The interval between the pair of blanking electrodes may vary accordingly. In this case, the electron beam cannot appropriately be deflected, and no desired pattern can be formed on a sample.
That is, in the conventional manufacturing method, it is difficult to manufacture a reliable blanking aperture array at a high yield.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above situation, and has as its object to provide a highly reliable array structure such as a blanking aperture array, a method of manufacturing such an array structure at a high yield, a charged particle beam exposure apparatus having such an array structure, and a device manufacturing method using such a charged particle beam exposure apparatus.
According to the first aspect of the present invention, there is provided a method of manufacturing an array structure having a plurality of openings and a plurality of pairs of opposing electrodes which are arranged in correspondence with each of the plurality of openings to control loci of a plurality of charged particle beams that pass through the plurality of openings, respectively. The manufacturing method is characterized by comprising a trench formation step of forming a plurality of pairs of opposing trenches in a substrate, a side-surface insulating layer formation step of forming an insulating layer on a side surface of each of the plurality of pairs of opposing trenches, a process step of processing the plurality of pairs of trenches to expose a conductive layer to a bottom portion of each of the plurality of pairs of opposing trenches, an electrode formation step of selectively growing a conductive material on the conductive layer exposed to the bottom portion of each of the plurality of pairs of trenches to fill the plurality of pairs of trenches with the conductive material, thereby forming a plurality of pairs of opposing electrodes, and an opening formation step of forming an opening between each of the pairs of opposing electrodes.
According to a preferred embodiment of the present invention, in the electrode formation step, the conductive material is preferably grown in the plurality of pairs of opposing trenches by plating using, as a plating electrode, the conductive layer exposed to the bottom portion of each of the plurality of pairs of opposing trenches.
When one of two surfaces of the substrate, where formation of the plurality of pairs of opposing trenches starts in the trench formation step, is defined as an upper surface side, the manufacturing method preferably further comprises a lower-surface-side insulating layer formation step of, before the trench formation step, forming an insulating layer on a lower surface side of the substrate, and a conductive layer formation step of, after the lower-surface-side insulating layer formation step before the process step, forming the conductive layer on the insulating layer on the lower surface side of the substrate.
Alternatively, the manufactu
Asano Kouji
Esashi Masayoshi
Iwasaki Yuichi
Moro Yoshiaki
Muraki Masato
Fernandez Kalimah
Lee John R.
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