CN212321440U

CN212321440U - System for large-area microscopic photoluminescence scanning and mapping measurement

Info

Publication number: CN212321440U
Application number: CN202020493761.6U
Authority: CN
Inventors: 蔡明聪; 洪瑜亨
Original assignee: Xuzhen Technology Co ltd
Current assignee: Xuzhen Technology Co ltd
Priority date: 2020-04-07
Filing date: 2020-04-07
Publication date: 2021-01-08
Anticipated expiration: 2030-04-07

Abstract

A system for large-area microscopic photoluminescence scanning and mapping measurement comprises a laser source for providing laser beams, a measuring platform for placing a workpiece to be measured and capable of carrying out displacement, a galvanometer scanning module with an X-Y optical scanning lens, a vision module, a spectrometer and a control unit, wherein the galvanometer scanning module is used for scanning the workpiece to be measured; when the laser beam is projected to a workpiece to be detected, a response beam of photoluminescence is generated, and the vision module and the spectroscope group connected with the spectrometer are arranged on a transmission path of the laser beam and the response beam; therefore, the set state of the related components is inspected and adjusted through the vision module, then the control unit drives the X-Y optical scanning lens and the measuring carrier to cooperatively displace, so that the laser beam is correspondingly projected on a position to be scanned, and the spectrometer records the spectral signal of the response light beam; the system repeatedly projects the laser beam and records the spectrum signal of the laser beam at the selected point, thereby completing the measurement operation of large-area point selection scanning.

Description

System for large-area microscopic photoluminescence scanning and mapping measurement

Technical Field

The present invention relates to a measurement system, and more particularly to a microscopic fluorescence scanning measurement system using the cooperative displacement of a galvanometer scanning module and a measurement stage to scan a laser beam at a selected point and record its response spectrum signal with a spectrometer.

Background

A Light-Emitting Diode (LED) is a semiconductor electronic component capable of Emitting Light, which has an oval appearance and a size of only one mung bean, but emits Light only at a grain (Die) portion thereof; at present, commercially, a boule is grown first, and is cut into a wafer, then epitaxy (single crystal film) of different materials is grown by using Metal Organic Chemical Vapor Deposition (Metal Organic Chemical Vapor Deposition), and a light emitting diode device structure is fabricated on the epitaxy, and finally, the boule is cut into a grain, and is packaged into a light emitting diode LED device.

The size of the LED crystal grain is about 1 millimeter (mm), and the LED crystal grain can only be used for manufacturing a single-color LED sign or a large-size television wall; however, with the evolution of technology, manufacturers have developed a "Micro light emitting diode (Micro LED)" with a side length less than 10 micrometers (μm), where the Micro LED is a display technology directly using RGB LEDs as self-luminous display point pixels and directly planting the pixels on a wafer; the principle of the LED structure is mainly to thin the film, miniaturize and array the LED structure design, and reduce the LED to at least 1% of the original LED, so that the LED structure has the characteristics of low power consumption, high brightness, ultrahigh resolution, color saturation and the like.

Photoluminescence (PL) is generated by irradiating a laser light source as an excitation source onto the surface of a light emitting diode, collecting light through an optical lens set, and entering a spectrometer to analyze the brightness and specific wavelength; in other words, before the epitaxy is packaged without being cut, the photoluminescence spectrum of the LED epitaxy is obtained by applying the principle of photoluminescence and the measurement and analysis of the spectrometer, so that the yield of the epitaxy process can be determined, the manufacturer can also determine whether the process conditions fall within the specification, and the quality status of the final product can be estimated.

Currently, one of the methods for detecting LED epitaxy in the industry is: changing a white light source of traditional Automatic Optical Inspection (AOI) into an externally-hung laser excitation source (side-beating type), exciting a workpiece to be detected in a large area, and realizing large-area mapping by using an X-Y translation table; however, after the surface of the led is laterally excited by an external laser source, the optical lens assembly receives the crystal grains in a large area and simultaneously generates photoluminescence (on the order of hundreds of micrometers to tens of millimeters), which results in an average result, and reduces the Signal-to-noise ratio (S/N); the spectral feature intensity analyzed by a subsequent spectrometer is an average value under a large area, although an X-Y translation stage is assisted to obtain a large-area photoluminescence spectral distribution graph of a workpiece to be measured, the spectral distribution graph can only be used as a reference due to the fact that a measurement result is an average value; this problem is more serious when the dies of the Micro LED are inspected, because when the inspection target is a Micro die, the average spectrum data in a large area will decrease the specific intensity of the die spectrum to be inspected, and the decrease of the Signal-to-noise ratio (S/N) will make the specific intensity of the die spectrum not easy to identify, thereby affecting the subsequent analysis.

Another conventional method for detecting the LED epitaxial spectrum is: guiding laser excitation light beams into a focusing lens group, focusing laser spots, exciting crystal grains in a small range area of a workpiece to be measured, and realizing large-area mapping by using an X-Y translation table; however, the introduction of a laser excitation light source into a focusing lens group can reduce the size of an excitation spot (reaching tens to hundreds of microns), thereby improving the defect that the spectral characteristic intensity is difficult to identify in a large area, but the realization of large-area mapping still adopts a traditional X-Y translation stage.

Another conventional method for detecting the LED epitaxial spectrum is as follows: some architectures are changed into Charge-coupled devices (CCD) instead of a spectrometer to analyze the photoluminescence spectrum of the workpiece to be detected; because the optical filter with specific wave band must be selected to satisfy the required corresponding photoluminescence spectrum of different workpieces to be tested, various corresponding optical filters must be added for replacement, and further the purchase cost of the equipment increases.

Because the number of crystal grains in the unit area of the micro light-emitting diode is at least thousands, and the brightness grades among the crystal grains are also different, the micro light-emitting diode adopts the existing detection mode of a large area, and the control of the epitaxial grade of the micro light-emitting diode cannot be met; moreover, the large-area mapping is realized only by using a platform mechanism with X-Y axial displacement, and the overlong detection time cannot meet the requirement of a mass production mode; therefore, how to perform fast scanning and determination of a large area and a small area by using photoluminescence becomes a topic to be considered and developed by the present invention.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a main purpose lies in using mirror scanning module and the displacement in coordination of measuring the microscope carrier to select some scanning and record with photoluminescence, make LED epitaxial wafer reach a micro-photoluminescence fluorescence scanning and measurement system of accurate classification.

To achieve the above object, the present invention discloses a system for large-area microscopic photoluminescence scanning and mapping measurement, which comprises: the laser source is used for providing a laser beam as an excitation light source of the workpiece to be detected; the measuring carrier is positioned on the opposite side of the laser light source and is provided with a working platform for placing a workpiece to be measured, and the working platform can carry out X, Y displacement in two axial directions at least; and the galvanometer scanning module is arranged above the working platform and positioned on a transmission path of the laser beam, is provided with an X-Y optical scanning lens and an optical reflecting lens, and realizes the focusing of laser spots and the generation of corresponding angle shift through the reflection of the optical reflecting lens and the focusing of the X-Y optical scanning lens, so that the laser beam is deflected and focused on a scanning point desired by the workpiece to be detected, the workpiece to be detected generates a photoluminescence response light beam, and the photoluminescence response light beam is received by the X-Y optical scanning lens and reflected by the optical reflecting lens so as to carry out the spectrum analysis of the response light beam.

A visual module connected with a first beam splitter group, wherein the first beam splitter group is positioned on a transmission path of the laser beam and the response beam, so that the visual module can be used for inspecting the relative position state of the laser beam projected on a desired scanning point and the response beam; the spectrometer is connected with a second spectroscope group, and the second spectroscope group is positioned on a transmission path of the laser beam and the response light beam, so that the spectrometer can be used for recording the spectrum signal of each scanning point; and the control unit is electrically connected with the measuring carrying platform, the galvanometer scanning module, the vision module and the spectrometer.

Therefore, a workpiece to be measured is placed on the working platform, the set state of the related components is inspected and adjusted through the vision module, then the control unit drives the X-Y optical scanning lens and the displacement mechanism to cooperatively displace, so that the laser beam is correspondingly projected on a desired scanning point, and the spectrometer is operated to record a spectral signal responded by each scanning point, thereby completing the measurement operation of large-area point selection scanning.

In an embodiment of the present invention, the laser source includes a laser machine and a beam splitter, the beam splitter is disposed on a transmission path of a laser beam projected by the laser machine for adjusting a reflection direction of the laser beam.

In an embodiment of the present invention, the vision module includes a lens and a CCD, and the lens and the CCD are disposed above the first beam splitter set for viewing the laser beam and the image of the response beam.

According to the technical characteristics, the utility model discloses a system for large tracts of land micro photoluminescence scanning and survey and drawing measurement, use the displacement of surveying microscope carrier to carry out the region of wanting to scan, and then carry out the point selection scanning of each point in the region through this galvanometer scanning module; the measurement carrier mainly moves in a large area, and the requirement of high-precision displacement does not exist, so that the measurement carrier is suitable for a low-cost mechanical displacement mechanism; and the scanning point by point is carried out in the area, the focusing of an X-Y optical scanning lens of the galvanometer scanning module and the angular deflection of an optical reflecting lens are applied, so that the accurate displacement and the sensitive reaction speed can be achieved; therefore, by measuring the cooperative displacement of the carrier and the galvanometer scanning module, the system can achieve the best operation benefits of mechanism combination and quick measurement.

Drawings

Fig. 1 is a schematic view of the measuring system of the present invention.

Fig. 2 is a front view of the measurement system assembly of the present invention.

Fig. 3 is an operation schematic diagram of the galvanometer scanning module of the present invention.

Description of reference numerals: 10-a frame body; 20-a laser light source; 21-laser optical machine; 22-a beam deflector; 30-a measuring stage; 31-a working platform; 32-a displacement mechanism; 40-galvanometer scanning module; a 41-X-Y optical scanning lens; 42-an optical mirror plate; 50-a vision module; 51-a first beam splitting mirror group; 52-lens; 53-CCD; 60-a spectrometer; 61-a second beam splitter group; 70-a control unit; l1-laser beam; m-workpiece to be measured; p-scanning point; r1-response beam; s-scanning the field of view.

Detailed Description

First, the utility model discloses a system for scanning of the micro photoluminescence of large tracts of land and survey and drawing are measured, as shown in fig. 1-2, contain: a frame body 10; a laser source 20 for providing a laser beam L1 as an excitation light source of the workpiece M to be measured, the laser source 20 including a laser optical machine 21 and a beam deflector 22 respectively disposed on the frame 10, and the beam deflector 22 being disposed on a transmission path of the laser beam L1 projected by the laser optical machine 21 for adjusting a reflection direction of the laser beam L1 and reducing an occupation space of the laser source 20; in the embodiment, the beam deflector 22 is configured with 2 stages, so that the laser beam L1 is projected in the horizontal direction after 2 reflections, which makes the laser source 20 occupy the least space and makes the adjustment of the laser beam L1 more flexible and convenient; a measuring carrier 30, disposed on the frame 10 and located at the opposite side of the laser light source 20, and having a working platform 31 for placing a workpiece M to be measured, and a displacement mechanism 32 capable of performing X, Y two axial displacements; in this embodiment, the displacement mechanism 32 further includes a Z-axis displacement function, so that the working platform 31 can be raised or lowered in height in accordance with the projection focal length of the laser beam L1; since the axial displacement function of the displacement mechanism 32 is the application of the existing technology, not the main appeal of the present invention, the action principle and mode thereof will not be described again; a galvanometer scanning module 40, disposed on the frame 10 and above the working platform 31, and on a transmission path of the laser beam L1, having an X-Y optical scanning lens 41 and an optical reflection lens 42, wherein the laser beam L1 is reflected by the optical reflection lens 42 to turn its horizontal projection direction downward, and then is focused by the X-Y optical scanning lens 41 to realize focusing of laser spots and generate corresponding angle shift, and the laser beam L1 is deflected and focused on a scanning point desired by the workpiece M to be measured, so that the workpiece M to be measured generates a photoluminescence response beam R1, and is reflected by the X-Y optical scanning lens 41 and the optical reflection lens 42 to make the response beam R1 transmit in the horizontal direction for performing spectrum analysis.

Then, a vision module 50 connected to a first beam splitter set 51 disposed on the frame 10, wherein the first beam splitter set 51 is located on a transmission path of the laser beam L1 and the response beam R1, so that the vision module 50 can be used to inspect the position and spot state of the laser beam L1 projected on the desired scanning point and the response beam R1; the vision module 50 further includes a lens 52 and a CCD53, and the lens 52 and the CCD53 are disposed above the first beam splitter group 51 for capturing an image of the response light beam R1; in this embodiment, an automatic optical inspection device (AOI analysis) may be further connected to improve the accuracy of the visual inspection; a spectrometer 60 connected to a second beam splitter group 61 disposed on the frame 10, wherein the second beam splitter group 61 is located on a transmission path of the laser beam L1 and the response beam R1, so that the spectrometer 60 can record a spectrum signal of each scanning point; and a control unit 70 disposed on the frame 10 and electrically connected to the measurement stage 30, the galvanometer scanning module 40, the vision module 50, and the spectrometer 60.

Therefore, the workpiece M to be measured is placed on the working platform 31, the laser optical machine 21 sends a laser beam L1 to turn to the horizontal direction through the beam deflector 22, and then the laser beam L1 in the horizontal direction is turned to the working platform 31 below through the refraction of the optical reflection lens 42, the setting state of the related components is inspected and adjusted through the vision module 50, then the control unit 70 drives the working platform 31 of the measurement carrier 30 to perform the displacement of the region to be scanned, after the scanning region is positioned, the angle deflection is performed through the optical reflection lens 42 of the galvanometer scanning module 40, so that the laser beam L1 is projected on the point to be scanned one by one correspondingly, and the spectrometer 60 is operated to record the spectral signal to which the spectrometer responds, in this embodiment, there are 9 scanning points in total in the scanning region, as shown in fig. 3; in the figure, each square represents the scanning visual field area S of the X-Y optical scanning lens 41 after the displacement of the measurement stage 30, and the laser beam L1 is projected onto the desired scanning point P one by one from the 1 st point at the upper left corner to the 9 th point at the lower right corner through the respective deflection of the optical reflection lens 42, and the responsive light beam R1 for scanning the photoluminescence of each point is received by the X-Y optical scanning lens 41 and reflected by the optical reflection lens 42, and the spectrum signal thereof is recorded by the spectrometer 60; after completing the scanning of each scanning point P in the scanning visual field area S and the recording of the signal, the measurement stage 30 will move to a new scanning visual field area S again, and repeatedly scan and record each scanning point P one by one, or selectively select a point to scan and record, and thus continuously and repeatedly perform in each scanning visual field area S one by one, thereby completing the measurement operation of large-area point selection scanning.

The utility model uses the measuring carrying platform 30 to carry out the displacement of the area to be scanned, and then carries out the scanning of each point in the area through the galvanometer scanning module 40; the measurement stage 30 mainly moves in a large area, and does not have the requirement of high-precision displacement, so that the measurement stage is suitable for a low-cost mechanical displacement mechanism; and the point-by-point scanning in the area can achieve accurate displacement and sensitive reaction speed by using the focusing of the X-Y optical scanning lens 41 of the galvanometer scanning module 40 and the angular deflection of the optical reflecting lens 42; therefore, by measuring the cooperative displacement of the carrier 30 and the galvanometer scanning module 40, the system can achieve the best operational benefits of mechanism combination and rapid measurement.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A system for large area microscopic photoluminescence scanning and mapping measurements, comprising:

a frame body;

the laser light source is arranged on one side of the frame body to provide a laser beam as an excitation light source of the workpiece to be detected;

the measuring carrier is arranged on the frame body and positioned on the opposite side of the laser light source, and is provided with a working platform and a displacement mechanism, so that a workpiece to be measured placed on the working platform can be subjected to at least X, Y axial displacements;

a galvanometer scanning module, which is arranged above the working platform and is positioned on a transmission path of the laser beam, is provided with an X-Y optical scanning lens and an optical reflection lens, and realizes the focusing of laser spots and the generation of corresponding angle shift through the reflection of the optical reflection lens and the focusing of the X-Y optical scanning lens, so that the laser beam is deflected and focused on a scanning point desired by the workpiece to be detected, and is projected to the workpiece to be detected to generate a response beam of photoluminescence, and the response beam is further received by the X-Y optical scanning lens and reflected by the optical reflection lens for spectrum analysis;

the visual module is connected with a first spectroscope group arranged on the frame body, and the first spectroscope group is positioned on a transmission path of the laser beam and the response beam, so that the visual module is used for inspecting the relative position state of the laser beam projected on a position to be scanned and the response beam;

the spectrometer is connected with a second spectroscope group arranged on the frame body, and the second spectroscope group is positioned on a transmission path of the laser beam and the response light beam, so that the spectrometer is used for recording the spectrum signal of each scanning point;

and the control unit is arranged on the frame body and is electrically connected with the measuring carrying platform, the galvanometer scanning module, the vision module and the spectrometer.

2. The system of claim 1, wherein the laser source comprises a laser light engine and a beam deflector disposed on a transmission path of the laser beam projected by the laser light engine for adjusting a reflection direction of the laser beam.

3. The system of claim 1, wherein the vision module comprises a lens and a CCD, the lens and the CCD being disposed above the first beam splitter group for viewing the laser beam and the image of the response beam.