CN2519295Y

CN2519295Y - Projection imaging objective lens for quasi molecule laser fine processing

Info

Publication number: CN2519295Y
Application number: CN 02200787
Authority: CN
Inventors: 左铁钏; 万盈; 陈涛
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2002-01-22
Filing date: 2002-01-22
Publication date: 2002-10-30
Anticipated expiration: 2012-01-22

Abstract

A projective imaging object lens used in the micro processing of quasi-molecular laser belongs to the laser micro processing and the applicable technical field of the laser micro processing and is characterized in that the projective imaging object lens comprises three spheroid quartz lens which are sequentially coaxially arranged in a lens seat, and a first lens is a negative lens 1 with irreversible orientation and a second positive lens 2 and a positive lens 3 with irreversible orientation are closely sequentially arranged on the lens seat with the first lens and the object lens is further characterized by adopting a negative lens 1 with positive double-sided curvature, a positive lens 2 with left positive double-sided curvature and right negative double-sided curvature and a negative lens 3 with positive double-sided curvature. The utility model with the resolution of 2 Mu m is especially used in the quasi-molecular laser wavelength area (248 n m), has high imaging quality and high energy transmission efficiency and can be applied in the method of mask projective imaging of quasi-molecular laser micro processing.

Description

The projection imaging object lens that the excimer laser microfabrication is used

Technical field

The projection imaging object lens that a kind of excimer laser microfabrication is used belong to Laser Micro-Machining and applied technical field thereof.It is that a kind of excimer laser that will be incident upon on the mask plate is imaged on the optical element on the processing work.Be mainly used in excimer laser mask projection microfabrication.

Background technology

The product size of excimer laser microfabrication is all in micron or sub-micrometer scale, and forming accuracy requires very high, this just need projection imaging system have high, near the image quality of diffraction limit, reach micron-sized resolution, big visual field and little distortion, depth of focus can not be too little, and the effect in order to guarantee to process, the transmitance of projection imaging system is had relatively high expectations to improve the capacity usage ratio of excimer laser, and this hopes for success again and has comparatively simple structure as system.Owing to the monochromaticity and the special wavelength (248nm) of excimer laser, its projection imaging system does not need correcting chromatic aberration simultaneously, but available lens material has only fused quartz a kind of.Therefore for being used for the micro-machined projection imaging system of excimer laser, need the parameter of the various aspects of choose reasonable object lens, comprise size, numerical aperture, imaging multiplying power and visual field size of conjugate distance or the like.

Summary of the invention

The purpose of this utility model is to overcome above deficiency, and a kind of used projection imaging object lens of the little processing mask projection of excimer laser imaging method that are used for are provided.

The technical solution of the utility model is seen the structural drawing 1 of projection imaging object lens.Technical scheme is characterised in that and includes in microscope base by 3 spherical quartz lens of mode co-axial alignment in turn, and wherein first for the irreversible negative lens 1 of orientation, is right after second positive lens 2 that is arranged in order and is orientated irreversible positive lens 3.It is positive negative lens 1 that feature also has been to adopt double-side curvature, the positive right negative positive lens 2 in a double-side curvature left side, and double-side curvature is positive positive lens 3.

The utility model is owing to provide a kind of used projection imaging object lens of the little processing mask projection of excimer laser imaging method that are used for, make being imaged on the processing work that the mask plate of excimer laser illumination can clear nothing distortion, and guarantee higher energy transmitance.

Accompanying drawing and subordinate list explanation

Fig. 1: be the structural drawing of projection imaging object lens, 1, double-side curvature is positive negative lens, 2, the positive right negative positive lens in a double-side curvature left side, 3, double-side curvature is positive positive lens;

Fig. 2: be projection imaging objective lens aberration curve map, (a) be object lens spherical aberration curve map, ordinate represents to be used to calculate the incident ray height of spherical aberration, and horizontal ordinate is represented corresponding spherical aberration numerical values recited.(b) be the sinusoidal dygorams of object lens, ordinate represents to be used to calculate the incident ray height of sinusoidal difference, and horizontal ordinate is represented corresponding sinusoidal difference value size.(c) be object lens curvature of field curve map, ordinate represents to be used to calculate the distance of meridional ray with the relative optical axis of sagittal ray of the curvature of field, and horizontal ordinate is represented corresponding meridianal curvature of field and sagitta of arc curvature of field numerical values recited;

Fig. 3: excimer laser projection imaging object lens use sample;

Fig. 4: for make in the use-case legend in kind of (i.e. the first arrow indication) used mask plate in position before the laser incident at Fig. 3;

Fig. 5: be the processing effect figure of mask pattern shown in Figure 4 through corresponding (i.e. the second arrow indication) gained behind the lens.

Table 1 is the structural parameters table of projection imaging object lens, and wherein R represents the spheric curvature value, and D represents with the first sphere position, the left side to be each sphere position of benchmark, and N represents each medium refraction index of incident.

Embodiment

Adopt structure shown in Figure 1, the optical material that this projection imaging objective system is adopted is that the trade mark is the optical quartz glass of JGS1.Laser beam transmission optics designing requirement had both been followed in the selection of the picture visual field of objective system parameter such as conjugate distance, numerical aperture, reduction magnification, system, imaging resolution etc., satisfied micro-machined requirement again.Object lens adopt 3 combination of lensess, and the 1st is negative lens, and all the other two is positive lens, and each sheet lens curvature and structural parameters are as shown in table 1.Fig. 2 is the aberration curve figure of total optical system of being combined into of

lens

1,2,3, is respectively spherical aberration, sinusoidal difference and the curvature of field.Reached the requirement of appointment by final aberration result and machining experiment proof resolution.

Among present embodiment Fig. 3, adopt excimer laser illumination one to comprise the mask plates (be marked with the square piezoid of NCLT word style and pattern among the figure, three groups of printed words live widths are divided into 100 μ m, 50 μ m, 20 μ m) of several groups of alphabetical compositions that vary in size.The image-forming objective lens that its

lens

1,2,3 constitute, its systematic parameter is: conjugate distance is 750mm, numerical aperture is 0.2, reduction magnification is 10, system be 1 * 1mm2 as the visual field, the imaging resolution of object lens is 2 μ m.Be placed on and see through in the excimer laser light path of mask plate, place the glass sheet that scribbles the PMMA photoresist at mask plate on through the corresponding image planes position that forms of image-forming objective lens institute, i.e. mask plate and photoresist glass sheet formation object-image relation.The excimer laser that sees through mask graph hollow out position is carried out etching processing to the PMMA photoresist.Then the photoetching glass sheet is taken out from light path, and the little shape pattern that etches is amplified observation at microscopically.The etching result of 2 μ m is high-visible among the result, not distortion, and as seen these object lens have reached the effect of initial design.

Claims

1, the projection imaging object lens used of a kind of excimer laser microfabrication, it is characterized in that including in microscope base by 3 spherical quartz lens of mode co-axial alignment in turn, wherein first is orientation irreversible negative lens (1), is right after second positive lens (2) that is arranged in order and is orientated irreversible positive lens (3).

2, the projection imaging object lens used of excimer laser microfabrication according to claim 1, having it is characterized in that adopting double-side curvature is positive negative lens (1), the positive right negative positive lens (2) in a double-side curvature left side, double-side curvature is positive positive lens (3).