Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Radiation mask
Patent
1995-05-26
1997-04-15
Rosasco, S.
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
Radiation mask
430 22, 430296, 430397, 156150, 1562722, G03F 900
Patent
active
056208146
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
a) Field of the Invention
The invention is directed to a process and an arrangement for producing dose profiles for the fabrication of structured surfaces with a beam which is used for exposure and is directed on the surface.
b) Description of the Related Art
Devices and processes employing the technique of variable dose writing to fabricate surface profiles for electron-beam lithography and photolithography are known (T. Fujita, H. Nishihara, J. Kayama, "Blazed grating and Fresnel lenses fabricated by electron-beam lithography", Opt. Lett. 7 (1982) 12, p. 578; M. Haruna, M. Takahishi, K. Wakahayhashi, H. Nishihara, "Laser beam lithographed Micro-Fresnel lenses", Applied Optics/Vol. 29, No. 34/1 December 1990).
The fact that the dissolve rate of a radiation-sensitive resist in the developer bath can be predetermined by the radiation dose introduced in the resist is made use of. Accordingly, it is possible to design the lateral radiation dose distribution in such a way that the desired surface profile is obtained after a certain period of time following development. FIG. 14 illustrates this procedure schematically.
However, the high cost of the facilities for producing the dose profiles required for this process poses problems, since the systems which have been used up to now, such as electron-beam writing devices or laser pattern generators, are physically large and very expensive. Further, very long processing times are necessary for extended surface profiles. The fabrication of micro-lenses and micro-lens arrays especially is highly time-consuming. Further, the amounts of data needed to write the required dose profiles are sometimes enormous, requiring a corresponding expenditure on computer technology.
OBJECT AND SUMMARY OF THE INVENTION
It is the object of the primary present invention to arrange the surface irradiation in such a way that the processing times and material outlay required for fabrication of micro-lenses and micro-lens arrays can be substantially reduced.
This object is met, according to the invention, by a process for producing dose profiles for the fabrication of structured surfaces with a beam used for exposure and directed on the surface, in that the beam has at least one shaped region in cross section, which shaped region is movable relative to the surface and whose extent in the movement direction of the relative movement, in combination with the velocity of the relative movement, determines the dose.
The relative movement is effected in at least one of two directions which are inclined at an angle relative to one another. The angle is advisably 90.degree., but may also diverge from 90.degree..
Parallel adjacent exposures are produced in the direction of relative movement for fabricating the lens array. It is also possible to use a rotating movement as relative movement.
Further, the subject of the invention is an optical arrangement for producing dose profiles for the fabrication of structured surfaces with a beam used for exposure and directed on the surface, in which a device is provided for shaping the cross section of the beam, which device generates at least one shaped region which is movable relative to the surface and whose extent in the direction of the relative movement, in combination with the velocity of the relative movement, determines the dose.
The device for shaping the cross section of the beam is advantageously a diaphragm whose aperture in the movement direction, in combination with the velocity of the relative movement, determines the dose.
The diaphragm can be a multiple diaphragm in which the individual diaphragms are arranged one behind the other in the movement direction, and the aperture of each individual diaphragm in the direction of relative movement determines the dose in combination with the velocity of the relative movement.
Piezo-actuators can be connected with the multiple diaphragm to produce the relative movement which substantially corresponds to the distance between the individual diaphragms in the movement direct
REFERENCES:
patent: 3893856 (1975-07-01), Bestenreinerm et al.
patent: 4609259 (1986-09-01), Suemitsu et al.
patent: 4935334 (1990-06-01), Boettiger et al.
patent: 5082755 (1992-01-01), Liu
patent: 5082762 (1992-01-01), Takahashi
patent: 5304441 (1994-04-01), Samuels et al.
Patent Abstract of Japan, vol. 7, No. 292 (E-219) (1437) 27 Dec. 1983, (JP, A, 58-166723 [Hitachi Seisakusho K.K.]).
Leica Lithographie Systeme Jena GmbH
Rosasco S.
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