CN110653488A

CN110653488A - Cross-scale high-resolution three-dimensional laser direct writing processing method

Info

Publication number: CN110653488A
Application number: CN201910981897.3A
Authority: CN
Inventors: 顾忠泽; 丁海波; 顾洪成; 郭一君
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2019-10-16
Filing date: 2019-10-16
Publication date: 2020-01-07

Abstract

The invention discloses a cross-scale high-resolution three-dimensional laser direct writing processing method, which comprises the following steps: (1) dividing the machining precision grade according to the appearance requirements of different areas of the target structure; (2) selecting corresponding focusing objective lenses and displacement tables for areas with different processing precision to generate corresponding processing paths; (3) in the laser direct writing processing process, performing polymerization processing according to a target path and objective lens selection; (4) and (5) developing and forming. The invention realizes the cross-scale high-precision micromachining method based on two-photon polymerization laser direct writing, and gives consideration to the machining precision of submicron scale and the integral structure of centimeter level; the focusing objective lenses with a plurality of numerical apertures are adopted, so that a plurality of processing precision choices are provided, and the limitation of a single focusing objective lens on the size of a focusing focus is solved; according to the different processing precision of different areas of the target structure, the processing efficiency is further improved, and the target size of laser direct writing is enlarged.

Description

Cross-scale high-resolution three-dimensional laser direct writing processing method

Technical Field

The invention relates to a laser direct writing method, in particular to a cross-scale high-resolution three-dimensional laser direct writing processing method.

Background

The laser direct writing technology based on two-photon polymerization utilizes the nonlinear optical action of femtosecond laser and substances to limit the polymerization reaction in a micro area of a laser focus. By selecting the wavelength of the laser and the numerical aperture of the focusing objective, the size of the laser focus can be controlled. Because the induction of two-photon polymerization requires that the laser energy reaches a certain threshold, the limitation of diffraction limit can be broken through by adjusting the laser energy and the exposure time while determining the size of the laser focus, and the preparation of a fine structure is realized. The direct writing preparation of a complex structure can be realized in a three-dimensional space by utilizing the space confinement effect of two-photon polymerization and matching with the relative movement of a laser focus and a target material. Therefore, the two-photon polymerization can meet the requirement of high-precision three-dimensional direct writing processing, and has wide application prospect in the fields of micro-nano optical devices, microelectronic systems, microfluidic channels, cell culture supports and the like.

In the prior art, a high-precision piezoelectric translation stage or a scanning galvanometer system is used for generating relative motion of a laser focus and a target material. The piezoelectric translation stage and the scanning galvanometer can ensure high-quality displacement precision, but the processing range of single processing is usually less than 300 microns. When a target structure with a larger size is faced, the whole processing is completed by using a splicing method, the processing period is longer, and the processing efficiency is low.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention aims to provide a cross-scale high-resolution three-dimensional laser direct writing processing method with high precision and high processing efficiency.

The technical scheme is as follows: the invention relates to a cross-scale high-resolution three-dimensional laser direct writing processing method, which comprises the following steps:

(1) in the horizontal direction and the vertical direction, the processing precision grades are divided according to the appearance requirements of different areas of the target structure, the size of the target structure in any direction in a three-dimensional space reaches 2 cm at most and 100 nm at least, and the processing precision grades are divided into 100 nm, 200 nm, 500 nm, 1 micron, 5 microns and 10 microns;

(2) selecting a corresponding focusing objective lens and a corresponding displacement platform for areas with different processing precision, wherein the focusing objective lens is any one of an oil immersion objective lens, a water immersion objective lens and a dry objective lens, the higher the precision requirement is, the larger the numerical aperture of the processing area is, the maximum numerical aperture is 1.4, the displacement platform is a combination of a piezoelectric displacement platform and an electric control displacement platform, and a corresponding processing path is generated by setting a corresponding segmentation interval according to the selection of the focusing objective lens;

(3) in the laser direct-writing processing process, the determined focusing objective lens and the generated path file are utilized for carrying out polymerization processing, the focusing objective lens is selected for different processing areas through an automatic switching device, and meanwhile, the position of a translation table is adjusted along the optical axis direction so that the focusing center positions of different objective lenses are the same;

(4) and (5) developing and forming.

The focusing objective lens comprises more than 4 objective lens with different numerical apertures. The objective lenses are arranged in an annular or linear manner.

Has the advantages that: compared with the prior art, the invention has the following remarkable characteristics:

1. the large-scale high-precision micromachining method is realized on the basis of two-photon polymerization laser direct writing, and the submicron-scale machining precision and the centimeter-level integral structure are considered;

2. the focusing objective lenses with a plurality of numerical apertures are adopted, so that a plurality of processing precision choices are provided, and the limitation of a single focusing objective lens on the size of a focusing focus is solved;

3. according to the different processing precision of different areas of the target structure, the proper focusing objective lens and the proper motion displacement platform are selected, so that the processing efficiency is further improved and the target size of laser direct writing is enlarged while various processing precisions of submicron to micron scales are provided.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of a first configuration of the focusing objective of the present invention;

FIG. 3 is a schematic view of a second configuration of the focusing objective of the present invention;

fig. 4 is a flow chart of the present invention.

Detailed Description

Referring to fig. 1, a photoresist 1 of a large-scale high-precision laser direct writing processing system is positioned on a target substrate 2. The incident laser 7 is focused on any position in the photoresist 1 through a focusing objective lens, the size of a focusing light spot can be controlled through an automatic switching device 6 of the focusing objective lens, and the effective polymer element and the processing precision can be controlled by adjusting the laser energy and the exposure time. In the processing process, the laser focus moves three-dimensionally relative to the photoresist to form a target structure through the movement of the piezoelectric translation stage 3 and the large-stroke electric control translation stage 4. The piezoelectric translation stage 3 adopts a three-dimensional piezoelectric translation stage with a stroke of 300 micrometers and a displacement resolution of 1 nanometer, and the large-stroke electric control translation stage 4 is a three-dimensional large-stroke electric control translation stage with a stroke of 25 millimeters and a displacement resolution of 100 nanometers.

As shown in fig. 2 to 3, during the machining process, the control system 5 controls the automatic focusing objective switching device 6 to select an appropriate focusing objective according to table 1 and select an appropriate piezoelectric translation stage 3 according to the size and accuracy requirement of the target area. The focusing objective is one of the following five: (1) oil lens, magnification 100, numerical aperture 1.4; (2) oil lens, magnification 63, numerical aperture 1.4; (3) an air mirror with magnification of 50 and numerical aperture of 0.75; (4) an air mirror with a magnification of 20 and a numerical aperture of 0.4; (5) air mirror, magnification 5, numerical aperture 0.1. The focus objective lens with larger numerical aperture is selected in the processing area with higher precision requirement. The focusing objective automatic switching device 6 is provided with 4 (more than) objective lenses with different numerical apertures, and the lenses are arranged in an annular or linear mode.

In the laser direct writing process, the focus objective lens automatic switching device 6 is used for selecting the formulated focus objective lenses for different processing areas, and meanwhile, the lens positions are adjusted to enable the focal positions of different focus objective lenses to be the same. The machining path sets the corresponding splitting interval according to the selection of the focusing objective, and the corresponding relation among the focusing objective, the translation stage and the splitting interval under different target accuracies is shown in table 1.

TABLE 1 comparison table of target precision, focusing lens, translation stage and cutting interval

As shown in fig. 4, the cross-scale high-resolution three-dimensional laser direct writing processing method includes the following steps:

(1) dividing the machining precision grade according to the appearance requirements of different areas of the target structure;

(2) selecting corresponding focusing objective lenses and displacement tables for areas with different processing precision to generate corresponding processing paths;

(3) in the laser direct writing processing process, performing polymerization processing according to a target path and an objective lens;

(4) and after the processing is finished, developing and forming.

The size of the target structure in any direction in a three-dimensional space reaches 2 cm at most, the characteristic size of the fine structure reaches 100 nm at least, and the machining precision grades are 100 nm, 200 nm, 500 nm, 1 micron, 5 microns and 10 microns.

Claims

1. A cross-scale high-resolution three-dimensional laser direct writing processing method is characterized by comprising the following steps:

(1) dividing machining precision grades in the horizontal direction and the vertical direction according to the precision requirement of the target structure;

(3) in the laser direct writing processing process, the determined focusing objective lens and the generated path file are utilized for carrying out polymerization processing:

(4) and (5) developing and forming.

2. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the size of the target structure in any direction in a three-dimensional space reaches 2 cm at most and 100 nm at least, and the processing precision grades are 100 nm, 200 nm, 500 nm, 1 micron, 5 microns and 10 microns.

3. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the focusing objective lens is any one of an oil immersion objective lens, a water immersion objective lens and a drying objective lens.

4. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the displacement table is a combination of a piezoelectric displacement table and an electric control displacement table.

5. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: and the processing path sets a corresponding segmentation interval according to the selection of the focusing objective lens.

6. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: in the laser direct writing process, focusing objective lenses are selected for different processing areas through an automatic switching device, and meanwhile, the position of a translation table is adjusted along the optical axis direction, so that the focusing center positions of different objective lenses are the same.

7. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the focusing objective lens includes 4 or more objective lens.

8. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the objective lenses are arranged in an annular or linear mode.