CN209894338U

CN209894338U - Sampling device for invisible light wave band erichian image

Info

Publication number: CN209894338U
Application number: CN201920840538.1U
Authority: CN
Inventors: 洪宜萍
Original assignee: NANJING DONGLILAI PHOTOELECTRIC INDUSTRIAL Co Ltd
Current assignee: NANJING DONGLILAI PHOTOELECTRIC INDUSTRIAL Co Ltd
Priority date: 2019-06-04
Filing date: 2019-06-04
Publication date: 2020-01-03
Anticipated expiration: 2029-06-04

Abstract

The utility model provides a find the focus position of measured object mirror easily, can swiftly obtain the non-visible light wave band sky of non-visible light wave band sky blue spot image sampling device of image. The device comprises a light source (1), a beam expander (2), a condenser (3), a pinhole plate (4), a beam splitter prism (5), a tube lens system (6), a measured object lens (7), a plane reflector (8) and a CCD (10); the non-visible light wave band collimated light beam emitted by the light source is expanded by the beam expander (2), is converged on a pinhole plate (4) at the focal position of the condenser through the condenser (3), is diffused by the pinhole plate, is emitted as parallel light through a tube lens system (6) after passing through the beam splitter prism (5), is focused on the surface of a plane reflector (8) through a measured object lens (7), and is reflected, returned along an original light path and focused on the target surface position of a sampling CCD (10) through the beam splitter prism (5); the position of the plane reflector (8) relative to the measured object mirror (7) on the optical axis can be adjusted.

Description

Sampling device for invisible light wave band erichian image

Technical Field

The technology relates to a device for sampling a non-visible light wave band erichsen image, which can detect the energy distribution of the non-visible light wave band erichsen image after sampling, in particular to a laser objective lens for laser invisible cutting, and can evaluate the uniformity of the focal energy distribution state for cutting after sampling the non-visible light wave band erichsen image.

Background

In the case of dicing a semiconductor chip using a laser lithography machine, a stealth dicing method is generally used to avoid scratching the chip surface by debris generated during dicing, as compared with the conventional dicing method, and the most significant difference of stealth dicing is a dicing technique in which laser light other than visible light is focused inside a workpiece material via an optical path system to form a starting point for dicing and the material is diced by cracking a crystal bond of the material. The cutting machine has the advantages of low cutting power, environmental protection, dust prevention, no need of cutting liquid, and little heat generated during cutting, which has no influence on the characteristics of workpiece materials.

Therefore, due to the change of the cutting method, the starting point for dividing is transferred from the surface of the traditional material to the interior of the workpiece material, the requirement on focusing capability of an optical path system used for focusing is higher, the roundness of a focus in the material and the energy distribution in the focus range are not good, the direction of cracking of the crystal bond is inconsistent with the depth of fracture, and the verticality of the cut edge of the material is affected. In order to facilitate adjustment and calibration, a laser cutting objective lens used in a focusing system is usually designed according to an adjustment wavelength and a working wavelength, wherein the adjustment wavelength is a visible light band, and the working wavelength is a non-visible light band, so that sampling of an airy spot image in the non-visible light band within a depth of field is difficult to realize, and of course, the roundness of the airy spot and the uniformity of energy cannot be accurately measured.

Disclosure of Invention

The utility model aims at providing a find the focus position of measured object mirror easily, can swiftly obtain the non-visible light wave band sky of non-visible light wave band sky blue spot image sampling device of image.

Non-visible light wave band eric spot image sampling device, include: the device comprises a light source 1, a beam expander 2, a condenser 3, a pinhole plate 4, a beam splitter prism 5, a tube lens system 6, a measured object lens 7, a plane reflector 8 and a CCD 10; the non-visible light wave band collimated light beam emitted by the light source 1 is expanded by the beam expander 2, then is converged on the pinhole plate 4 at the focal position of the condenser through the condenser 3, is diffused by the pinhole plate, is emitted as parallel light through the tube lens system 6 after passing through the beam splitter 5, is focused on the surface of the plane reflector 8 through the measured object lens 7, is reflected by the light, returns along the original light path, and is focused on the target surface position of the sampling CCD10 through the beam splitter 5; the position of the plane mirror 8 on the optical axis relative to the object-to-be-measured mirror 7 can be adjusted.

In the non-visible light wave band airy spot image sampling device, the light source 1 is a collimating non-visible light wave band laser.

The above-mentioned sampling device for the ericardian image of non-visible light wave band also includes a height meter 9 for detecting the moving distance of the plane reflector 8 relative to the measured objective 7.

According to the sampling device for the erichian image in the non-visible light wave band, the focal length of the tube mirror system is 6 =200 mm.

The beneficial effect of this technique: the non-visible light wave band collimation laser beam emitted by the light source 1 is expanded by the beam expander 2, then is converged by the condenser 3 and then is on the pinhole plate 4 of the focal position of the condenser, the light beam is diffused by the pinhole plate, is emitted as parallel light through the tube lens system 6 after passing through the beam splitter 5, is focused on the surface of the plane reflector 8 through the measured object lens 7, the light is reflected and returns along the original light path, and is focused on the target surface position of the sampling CCD10 through the beam splitter 5, at the moment, the focal position of the measured object lens 7 is found by adjusting the upper and lower positions of the plane reflector 8 within the depth of field range of the measured object lens 7, and then the plane reflector 8 is moved on the optical axis near the focal position, thus the Ehrlich spot images of different positions within the depth of field range can be obtained on the CCD. The positions of the pinhole 4 and the CCD10 target surface in the device are a set of conjugate points.

Because the light source adopts the collimation laser of the non-visible light wave band, the problem that the energy uniformity and the roundness of the airy piebal under the working wavelength cannot be accurately measured in the field depth range because the working wavelength is the non-visible light wave band is solved.

When the device is used, the measured object mirror is placed on the designated installation surface, the main optical axis of the measured object mirror is coincided with the system optical axis, the focal position of the measured object mirror 7 is found by adjusting the upper position and the lower position of the plane reflecting mirror 8, and the Ehrlich spot images at different positions in the depth of field range are sampled according to the reading of the height meter 9. And finally, inputting the sampling result into a computer, and measuring the energy distribution and the roundness of the acquired erichsen spots at different positions in the field depth range by adopting the prior art to obtain the results of the energy distribution and the roundness of the erichsen spots.

Drawings

FIG. 1 is a schematic diagram of an image sampling apparatus for an Ehrlich patch in the non-visible band;

FIG. 2 is a result of sampling airy plaques at different positions within the depth of field using the apparatus;

FIG. 3 is an algorithm processed airy disk profile;

FIG. 4 is a profile of the maximum inscribed circle of the airy disk after algorithm processing;

FIG. 5 is an energy distribution plot of an airy disk after being processed by an algorithm;

fig. 6 is a graph of the energy distribution of the focus area after being processed by the algorithm.

Detailed Description

The present technology is further described below with reference to the accompanying drawings and examples.

The method for detecting the energy of the invisible light wave band airy spot firstly adopts a sampling device of the invisible light wave band airy spot pattern shown in figure 1 to sample. The non-visible light wave band collimation laser beam emitted by the light source 1 is expanded by the beam expander 2, then is converged by the condenser 3 and then is emitted out through the condenser focal point position pinhole plate 4, the light beam is diverged through the pinhole plate, is emitted out through the beam splitter 5 and then is emitted as parallel light through the focal length =200mm tube lens system 6, is focused on the surface of the plane reflector 8 through the rear diaphragm of the measured object lens 7, the light is reflected and returns along the original light path, and is focused on the target surface position of the sampling CCD10 through the beam splitter 5, at the moment, the focal point position of the measured object lens 7 is found by adjusting the upper and lower positions of the plane reflector 8 within the depth of field range of the measured object lens 7, and then the Ehrlich spot images at different positions within the depth of the scene range are sampled according to the reading of the height gauge 9, and the positions of the pinhole 4 and the sampling CCD10 target surface in the system are a.

Referring to fig. 2, after finding the focus position of the objective lens 7 to be measured, the altimeter 9 is reset to zero, the readings of the altimeter 9 are recorded in sequence by adjusting the upper and lower positions of the plane mirror 8, and the airy speckles at different defocused positions are sampled by the CCD at the time.

Referring to fig. 3, the image of the airy spot is input into a computer and the outline of the airy spot is identified by an algorithm belonging to the prior art, as shown in fig. 3.

Referring to fig. 4, the maximum inscribed circle contour in the airy disk contour in the sampling result is obtained after algorithm processing by using the maximum inscribed circle judgment rule. The ratio of the area of the largest inscribed circle to the area occupied by the airy spot profile was calculated by integration, resulting in a true circularity value (ratio of areas) K = 0.9234.

Referring to fig. 5, a contour map of the airy plaque energy distribution is obtained by an algorithmic process. As shown in fig. 6.

Referring to fig. 6, the energy distribution graphs of the focal area are compared through algorithm processing, and whether the energy distribution of the airy disk at the position is uniform or not is judged.

By sampling and detecting calculation through the sampling device, aiming at an objective lens for laser invisible cutting, the energy distribution and the roundness of the Ehrlich spots under a non-visible light wave band can be quickly and accurately sampled, analyzed, evaluated and detected as well as the image quality.

Claims

1. A sampling device for an Erie spot image in a non-visible light wave band is characterized in that: it includes: the device comprises a light source (1), a beam expander (2), a condenser (3), a pinhole plate (4), a beam splitter prism (5), a tube lens system (6), a measured object lens (7), a plane reflector (8) and a CCD (10); the non-visible light wave band collimated light beam emitted by the light source (1) is expanded by the beam expander (2), then is converged on a pinhole plate (4) at the focal position of the condenser through the condenser (3), is diffused by the pinhole plate, is emitted as parallel light through a tube lens system (6) after passing through the beam splitter prism (5), is focused on the surface of a plane reflector (8) through a measured object lens (7), is reflected, returns along the original light path, and is focused on the target surface position of the sampling CCD (10) through the beam splitter prism (5); the position of the plane reflector (8) relative to the measured object mirror (7) on the optical axis can be adjusted.

2. The non-visible band airy spot image sampling apparatus of claim 1, wherein: the light source (1) is a quasi-straight non-visible light wave band laser.

3. The non-visible band airy spot image sampling apparatus of claim 1, wherein: it also comprises an altimeter (9) for detecting the moving distance of the plane reflector (8) relative to the measured objective (7).

4. The non-visible band airy spot image sampling apparatus of claim 1, wherein: focal length of the tube lens system (6) =200 mm.