CN114130709A - LED crystal grain appearance detection method - Google Patents
LED crystal grain appearance detection method Download PDFInfo
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- CN114130709A CN114130709A CN202111198694.0A CN202111198694A CN114130709A CN 114130709 A CN114130709 A CN 114130709A CN 202111198694 A CN202111198694 A CN 202111198694A CN 114130709 A CN114130709 A CN 114130709A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
- B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
- B07C5/34—Sorting according to other particular properties
- B07C5/342—Sorting according to other particular properties according to optical properties, e.g. colour
- B07C5/3422—Sorting according to other particular properties according to optical properties, e.g. colour using video scanning devices, e.g. TV-cameras
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
- B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
- B07C5/02—Measures preceding sorting, e.g. arranging articles in a stream orientating
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
- B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
- B07C5/34—Sorting according to other particular properties
- B07C5/342—Sorting according to other particular properties according to optical properties, e.g. colour
- B07C5/3425—Sorting according to other particular properties according to optical properties, e.g. colour of granular material, e.g. ore particles, grain
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
- B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
- B07C5/36—Sorting apparatus characterised by the means used for distribution
- B07C5/361—Processing or control devices therefor, e.g. escort memory
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
- B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
- B07C5/36—Sorting apparatus characterised by the means used for distribution
- B07C5/361—Processing or control devices therefor, e.g. escort memory
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Abstract
The invention discloses an LED crystal grain appearance detection method, which comprises the steps of carrying out optical detection on an LED crystal grain to obtain an appearance parameter document; dividing the LED crystal grains into first qualified crystal grains, first unqualified crystal grains and suspicious crystal grains according to the appearance parameter document; acquiring a picture of a suspicious crystal grain, and judging the type of the appearance defect of the suspicious crystal grain according to the picture of the suspicious crystal grain; and dividing the suspicious crystal grains into second qualified crystal grains and second unqualified crystal grains according to the appearance defect types. The detection method can be used for carrying out re-judgment at the wafer stage, unqualified crystal grains can be selected in time, and the unqualified crystal grains are prevented from being sorted and arranged on finished product wafers, so that the manual visual inspection step is omitted, and a large amount of manpower and microscope cost are saved.
Description
Technical Field
The invention relates to the technical field of light emitting diodes, in particular to a method for detecting the appearance of an LED crystal grain.
Background
After the LED wafer completes electrical parameter testing, Automatic Optical Inspection (AOI) of appearance, and sorting of good wafers, the same grade of crystal grains on the LED wafer are selected to the square wafer, and finally, the appearance of the finished square wafer is manually inspected again, and the abnormal crystal grains missed by AOI Inspection are removed, so as to ensure that the appearance of each crystal grain meets the quality requirement of shipment.
Because the AOI detection capability cannot reach 100%, a small part of abnormal crystal grains can be selected to a square sheet, and therefore manual re-inspection through a microscope is needed, a large amount of manpower and microscope equipment are consumed in the mode, namely, 100% of finished product crystal grains need to be inspected in order to remove 1% of unqualified crystal grains, and 99% of time is useless, so that the efficiency and the labor cost are greatly influenced.
In addition, the manual microscope picking method is easy to miss picking and miss picking due to limited microscope visual field, so that abnormal crystal grains are not picked, and quality abnormality is caused.
Disclosure of Invention
The invention aims to solve the technical problem of providing an LED crystal grain appearance detection method which is high in efficiency, low in cost and high in detection rate of unqualified crystal grains.
In order to solve the above technical problem, the present invention provides a method for detecting an appearance of an LED die, including:
carrying out optical detection on the LED crystal grains to obtain an appearance parameter document, wherein the appearance parameter document comprises the defect area proportion of the crystal grains;
dividing the LED crystal grains into first qualified crystal grains, first unqualified crystal grains and suspicious crystal grains according to the appearance parameter document, wherein the area proportion of the crystal grains of the suspicious crystal grains is within a preset range, the area proportion of the crystal grains of the first qualified crystal grains is smaller than the preset range, and the area proportion of the crystal grains of the first unqualified crystal grains is larger than the preset range;
acquiring a picture of a suspicious crystal grain, and judging the type of appearance defects of the suspicious crystal grain according to the picture of the suspicious crystal grain, wherein the type of the appearance defects comprises epitaxial appearance defects and pollution appearance defects;
and dividing the suspicious crystal grains into second qualified crystal grains and second unqualified crystal grains according to the types of the appearance defects, wherein if the types of the appearance defects of the suspicious crystal grains are epitaxial appearance defects, the suspicious crystal grains are second unqualified crystal grains, if the types of the appearance defects of the suspicious crystal grains are polluted appearance defects, the suspicious crystal grains are second qualified crystal grains, the first qualified crystal grains and the second qualified crystal grains form qualified crystal grains, and the first unqualified crystal grains and the second unqualified crystal grains form unqualified crystal grains.
As an improvement of the above solution, the appearance parameter document further includes a die defect area, where a die defect area ratio is a die defect area/a die light-emitting area, the die light-emitting area refers to an area of an orthographic projection of the LED die on the light-emitting surface of the optical detection device, and the die defect area is a total area of an orthographic projection of the LED die on the optical detection device.
As an improvement of the above scheme, the epitaxial appearance defect refers to an appearance defect caused by an epitaxial defect of an LED die, and the contaminated appearance defect refers to an appearance defect caused by external contamination during a manufacturing process of an LED die.
As an improvement of the scheme, the appearance defects comprise one or more of electrode dropping, luminous layer dropping, scratches, pollutants, depressions and cracks.
As an improvement of the above scheme, the method for dividing the LED dies into the first qualified dies, the first unqualified dies and the suspect dies comprises:
setting a first judgment standard, wherein if the area ratio of the crystal grain defects of the LED crystal grains is smaller than or equal to the first judgment standard, the LED crystal grains are primarily selected crystal grains, and if the area ratio of the crystal grain defects of the LED crystal grains is larger than the first judgment standard, the LED crystal grains are first unqualified crystal grains;
setting a second judgment standard, wherein if the area ratio of the crystal grain defect of the primary selected crystal grain is smaller than the second judgment standard, the primary selected crystal grain is a first qualified crystal grain, and if the area ratio of the crystal grain defect of the primary selected crystal grain is larger than or equal to the second judgment standard, the primary selected crystal grain is a suspicious crystal grain;
wherein, the area ratio of the crystal grain defects in the second judgment standard is smaller than that in the first judgment standard.
As an improvement of the above, the ratio of the area of the grain defect in the first judgment standard is 30% to 60%, and the ratio of the area of the grain defect in the second judgment standard is 10% to 40%.
As an improvement of the above scheme, the suspicious crystal grains are scanned to generate a picture of the suspicious crystal grains;
and transmitting the picture of the suspicious grains to a display device, judging the appearance defect type of the suspicious grains according to the picture of the suspicious grains, and dividing the suspicious grains into second qualified grains and second unqualified grains.
As an improvement of the above scheme, the LED die appearance inspection method further includes:
acquiring the position information of the LED crystal grains, wherein the position information of the LED crystal grains comprises the position information of qualified crystal grains and the position information of unqualified crystal grains;
obtaining appearance information of qualified crystal grains and appearance information of unqualified crystal grains according to the position information and the appearance parameter document of the LED crystal grains;
and classifying the qualified crystal grains into good grade and classifying the unqualified crystal grains into bad grade according to the appearance information of the qualified crystal grains and the appearance information of the unqualified crystal grains.
As an improvement of the above solution, the method for acquiring the position information of the LED die includes:
carrying out optical detection on the LED crystal grains, and acquiring position information of the LED crystal grains while acquiring an appearance parameter document, wherein the position information of the LED crystal grains comprises position information of first qualified crystal grains, position information of first unqualified crystal grains and position information of suspicious crystal grains;
scanning the suspicious crystal grains to obtain the suspicious crystal grain picture and position information of the suspicious crystal grains, wherein the position information of the suspicious crystal grains comprises the position information of second qualified crystal grains and the position information of second unqualified crystal grains;
the position information of the first qualified crystal grains and the position information of the second qualified crystal grains form the position information of the qualified crystal grains, and the position information of the first unqualified crystal grains and the position information of the second unqualified crystal grains form the position information of the unqualified crystal grains.
As an improvement of the above scheme, the sorting device arranges the qualified crystal grains onto a finished product square according to the appearance information of the qualified crystal grains, and the appearance qualification rate of the LED crystal grains on the finished product square is 100%.
The implementation of the invention has the following beneficial effects:
the detection method is a brand-new LED crystal grain appearance detection method, re-judgment is carried out at the wafer stage, unqualified crystal grains can be selected in time, and the unqualified crystal grains are prevented from being sorted and arranged on finished product squares, so that the step of manual visual inspection is omitted, and a large amount of labor and microscope cost is saved.
The detection method generates the suspicious crystal grains into pictures for re-judgment, and the observation visual field and the definition of the pictures are better than those of a microscope, so that the detection rate and the accuracy rate of unqualified crystal grains are high.
The detection method can simultaneously display a plurality of pictures of the suspicious grains on the display device, so that the pictures of the suspicious grains can be compared and judged, and not only is the operator, but also the accuracy of the re-judgment can be improved.
According to the detection method, due to the fact that the position information and the appearance information of the suspicious crystal grains are collected, fine statistics of unqualified crystal grains can be achieved, the improvement and the quality improvement of the previous process are facilitated, and multiple rechecking of the unqualified crystal grains and accurate tracing of the wafer can be achieved.
Drawings
FIG. 1 is a diagram of 2 suspicious grains in an embodiment of the present application;
fig. 2 is a picture of 12 suspicious grains in the embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.
The application provides a method for detecting the appearance of an LED crystal grain, which comprises the following steps:
s1, carrying out optical detection on the LED crystal grains to obtain an appearance parameter document, wherein the appearance parameter document comprises the defect area proportion of the crystal grains;
optical inspection is an appearance inspection method of an LED die to determine whether the appearance of the LED die meets requirements, and specifically, inspection standards are set according to the application field of the LED die and the requirements of customers.
Preferably, the LED crystal grains are placed in an automatic appearance optical detection device for optical detection.
The appearance parameter document further comprises a crystal grain defect area, wherein the crystal grain defect area ratio is the crystal grain defect area/crystal grain light-emitting area, the crystal grain light-emitting area refers to the area of the light-emitting surface orthographic projection of the LED crystal grain on the optical detection equipment, and the crystal grain defect area is the total area of the defect orthographic projection of the LED crystal grain on the optical detection equipment.
S2, dividing the LED crystal grains into first qualified crystal grains, first unqualified crystal grains and suspicious crystal grains according to the appearance parameter document;
specifically, the method for dividing the LED dies into the first qualified dies, the first unqualified dies, and the suspicious dies includes:
s21, setting a first judgment standard, wherein if the area proportion of the crystal grain defects of the LED crystal grains is smaller than or equal to the first judgment standard, the LED crystal grains are primarily selected crystal grains, and if the area proportion of the crystal grain defects of the LED crystal grains is larger than the first judgment standard, the LED crystal grains are first unqualified crystal grains;
s22, setting a second judgment standard, wherein if the area proportion of the crystal grain defect of the primary selected crystal grain is smaller than the second judgment standard, the primary selected crystal grain is a first qualified crystal grain, and if the area proportion of the crystal grain defect of the primary selected crystal grain is larger than or equal to the second judgment standard, the primary selected crystal grain is a suspicious crystal grain;
wherein, the area ratio of the crystal grain defects in the second judgment standard is smaller than that in the first judgment standard.
In the conventional LED die appearance inspection method, after the LED die is optically inspected in step S1, the LED die is separated into a qualified die and an unqualified die by the first judgment criterion only, but a small portion of abnormal die (unqualified die) is left in the qualified die. If the first judgment standard is increased, the defect area ratio of the crystal grains is set to be small, the number of unqualified crystal grains is increased, and some LED crystal grains meeting the requirements are divided into unqualified crystal grains, so that waste is caused, and the cost is increased.
In order to select the small part of abnormal grains, the qualification rate of finished product grains on the square piece reaches 100%, and meanwhile, the cost can be reduced.
The second judgment standard is stricter than the first judgment standard, wherein the area proportion of the crystal grain defect in the second judgment standard is smaller than that of the crystal grain defect in the first judgment standard, so that unqualified crystal grains with large area proportion of the crystal grain defect are removed through the first judgment standard, qualified crystal grains with small area proportion of the crystal grain defect are removed through the second judgment standard, and finally suspicious crystal grains with small area proportion of the crystal grain defect in a preset range are selected for re-judgment, so that the misjudgment of abnormal crystal grains as qualified crystal grains can be avoided, the misjudgment of qualified crystal grains as unqualified crystal grains can be avoided, the qualification rate of finished product crystal grains on the square piece is improved, and the cost is reduced.
Taking 100 LED dies as an example, the defect area ratio of the LED dies in the first judgment standard is set to 40%, and the defect area ratio of the dies in the second judgment standard is set to 20%, wherein the defect area ratio of 90 LED dies is less than or equal to 40%, the defect area ratio of 10 LED dies is greater than 40%, the defect area ratio of 80 LED dies in 90 LED dies is less than 20%, and the defect area ratio of 10 LED dies is greater than or equal to 20% and less than or equal to 40%.
Because the defect area ratio of the LED dies in the first judgment standard is 40%, 10 first unqualified dies and 90 primary selected dies are included in the 100 LED dies;
since the defective area ratio of the dies in the second criterion is 20%, 80 first qualified dies and 10 suspicious dies are included in the 90 primary selected dies.
After the step is completed, 10 first unqualified dies and 80 first qualified dies are completed, appearance detection is completed, the LED dies can be sorted and arranged on a square piece, and the detection accuracy of the existing AOI equipment for the dies is 100% because the defect area ratio of the first qualified dies and the first unqualified dies is strict.
In the appearance detection method of the LED crystal grains, in addition to the qualified crystal grains and the unqualified crystal grains are divided according to the defect area ratio of the crystal grains, the qualified crystal grains and the unqualified crystal grains are also required to be divided according to the appearance defect types of the crystal grains. The appearance defect types include epitaxial appearance defects and contaminated appearance defects. The existing AOI equipment is difficult to distinguish whether the appearance defect type of the crystal grains is a pollution appearance defect or an epitaxial appearance defect.
In addition, since the defect area ratio of the LED die with the epitaxial appearance defect is small, the LED die can be determined as a qualified die, and the defect area ratio of the LED die with the appearance defect contaminated is not so strict, if the qualified die and the unqualified die are divided only by the defect area ratio, the misdetermination is easily caused.
The defect area ratio of the 10 suspicious crystal grains is more than or equal to 20% and less than or equal to 40%, if the qualified crystal grains and the unqualified crystal grains are divided only by the defect area ratio, the 10 suspicious crystal grains can be divided into the qualified crystal grains, but the appearance defect type of partial crystal grains is an epitaxial appearance defect, the appearance defect type is a crystal grain with the epitaxial appearance defect, the defect area ratio of the suspicious crystal grains is less than 20% and can be divided into the qualified crystal grains, and the defect area ratio of the suspicious crystal grains is more than or equal to 20% and is divided into the unqualified crystal grains; the appearance defect type of some crystal grains is a dirty appearance defect, and the crystal grains can be classified as qualified crystal grains as long as the defect area ratio is less than or equal to 40%.
Because the appearance defect type of the crystal grain is difficult to distinguish by the existing AOI equipment whether the crystal grain is a polluted appearance defect or an epitaxial appearance defect, the LED crystal grain is divided into the first qualified crystal grain, the first unqualified crystal grain and the suspicious crystal grain by the first judgment standard and the second judgment standard, and then the suspicious crystal grain is subjected to re-judgment so as to divide the suspicious crystal grain into the second qualified crystal grain and the second unqualified crystal grain.
Preferably, the area ratio of the grain defect in the first judgment standard is 30% to 60%, and the area ratio of the grain defect in the second judgment standard is 10% to 40%. By setting the area proportion of the grain defects in the first judgment standard and the second judgment standard, the detection efficiency can be effectively improved.
S3, obtaining a picture of the suspicious crystal grain, and judging the appearance defect type of the suspicious crystal grain according to the picture of the suspicious crystal grain, wherein the appearance defect type comprises an epitaxial appearance defect and a pollution appearance defect;
specifically, the suspicious crystal grains are scanned to generate a picture of the suspicious crystal grains, and the appearance defect types of the suspicious crystal grains are judged according to the picture of the suspicious crystal grains, wherein the appearance defect types include an epitaxial appearance defect and a contaminated appearance defect.
The method and the device can scan the suspicious crystal grains through the camera of the AOI equipment or the external camera to obtain the picture of the suspicious crystal grains, and then can transmit the picture of the suspicious crystal grains to the display equipment.
S4, dividing the suspicious grains into second qualified grains and second unqualified grains according to the appearance defect types;
if the type of the appearance defect of the suspicious crystal grain is an epitaxial appearance defect, the suspicious crystal grain is a second unqualified crystal grain, if the type of the appearance defect of the suspicious crystal grain is a polluted appearance defect, the suspicious crystal grain is a second qualified crystal grain, the first qualified crystal grain and the second qualified crystal grain form a qualified crystal grain, and the first unqualified crystal grain and the second unqualified crystal grain form an unqualified crystal grain.
The appearance defect types of the suspicious crystal grains are classified into a polluted appearance defect and an epitaxial appearance defect, wherein the LED crystal grains belonging to the polluted appearance defect are judged to be second qualified crystal grains as long as the defect area of the LED crystal grains is less than or equal to 40%; if the appearance defect of the suspicious crystal grain is an epitaxial appearance defect and the defect area ratio is less than 20%, the suspicious crystal grain is judged to be a second unqualified crystal grain.
Referring to fig. 1, the ratio of the area of two suspicious dies in the figure is less than or equal to 40%, so that in the first judgment standard, the two suspicious dies cannot be found out by the conventional AOI method, and therefore, in the subsequent steps, the abnormal LED dies missed by AOI detection need to be picked up and removed from the finished product by a manual visual inspection method, so as to ensure that the appearance of each LED die meets the quality requirement of shipment.
If the area ratio of the defect in the first judgment standard is reduced, the qualified die is easily determined as the unqualified die by mistake, which causes waste and reduces the yield. Therefore, the LED dies are detected only by the first determination criterion, and the detection rate of the unqualified dies cannot be 100%.
In order to solve the problems, suspicious grains are selected from the normal grains by setting a second judgment standard, and then the suspicious grains are subjected to re-judgment so as to improve the detection rate of the unqualified grains of the AOI.
Firstly, sorting the LED crystal grains according to the appearance defect types of the LED crystal grains, and classifying the appearance defect types of the suspected crystal grains into pollution appearance defects and epitaxial appearance defects; due to the fact that the unqualified crystal grains have different requirements on the defect area ratio of the LED crystal grains with the polluted appearance defects and the defect area ratio of the LED crystal grains with the epitaxial appearance defects, the suspicious crystal grains are selected through the second judgment standard.
Next, as shown in two suspicious crystal grains in fig. 1, the appearance defect type of the suspicious crystal grains on the left side is a contaminated appearance defect, the appearance defect of the suspicious crystal grains on the right side is an epitaxial appearance defect, and it is difficult for the existing AOI to distinguish whether the defect of the suspicious crystal grains is a contaminated appearance defect or an epitaxial appearance defect. Although the AOI has low judgment precision on the defect of the polluted appearance and the defect of the epitaxial appearance, after the picture is generated, the artificial judgment is easy to judge whether the defect of the LED crystal grain is the defect of the polluted appearance or the defect of the epitaxial appearance.
The appearance defect includes one or more of electrode dropping, light emitting layer dropping, scratch, contaminant sticking, dent and crack, but is not limited thereto.
Specifically, suspicious crystal grains can be scanned by a camera of the AOI device itself or an external camera to obtain a picture of the suspicious crystal grains, and then the picture of the suspicious crystal grains can be transmitted to the display device, and unqualified crystal grains are selected from the suspicious crystal grains according to the picture of the suspicious crystal grains.
In the existing manual visual inspection method, the LED crystal grains on the finished product square are inspected through a microscope, the inspection area is limited, a large amount of microscope equipment and visual inspection personnel are needed, the cost is high, and the efficiency is low.
After the picture is generated by the suspicious crystal grains, the pictures of the suspicious crystal grains can be transmitted to the display equipment for judgment, as shown in fig. 2, the visual field can be enlarged, the definition of the pictures can be improved, in addition, the pictures can be displayed and judged simultaneously, the operation side is simplified, and the accuracy of repeated judgment can be improved.
Referring to fig. 2, 12 LED dies in fig. 2 are suspicious dies, wherein the appearance defects of suspicious dies No. 1, 2, 3, 5, 7, and 12 are general contaminated appearance defects, and the ratio of 20% to 40% of the defective area is within the acceptable range, so that suspicious dies No. 1, 2, 3, 5, 7, and 12 are determined as acceptable dies; although the defect area ratio of No. 4, 6, 8, 9, 10, 11 suspicious crystal grains is 20% or more and 40% or less, the appearance defect is an epitaxial appearance defect, and therefore No. 4, 6, 8, 9, 10, 11 suspicious crystal grains are judged as defective crystal grains.
Specifically, the suspicious crystal grains in fig. 2 can be clicked to be judged as unqualified crystal grains; or click on the corresponding location of the suspect grain in fig. 2 (e.g., the box under the suspect grain, the box over the suspect grain, the box to the left of the suspect grain, etc.).
Because the LED crystal grains detected on the AOI equipment are still on the wafer, after the AOI detection, the LED crystal grains judged to be qualified crystal grains need to be arranged on a finished product wafer through sorting equipment, and then the finished product can be formed.
In order to avoid the sorting equipment from arranging unqualified crystal grains on a finished product square to ensure that the LED crystal grains on the finished product square are 100% qualified crystal grains, the method and the device obtain the picture of the suspicious crystal grains and also obtain the position information of the suspicious crystal grains.
Specifically, the suspicious crystal grains can be scanned through a camera of the AOI equipment or an external camera, and the position information of the suspicious crystal grains can be obtained by constructing an XY axis system.
After unqualified crystal grains are selected from the suspicious crystal grains, the appearance information of the unqualified crystal grains can be recorded through the position information of the unqualified crystal grains. As shown in fig. 2, after the No. 4 suspicious die is determined as a failed die, the present application records appearance information (such as defect area ratio, defect type, etc.) of the die according to the position information (such as coordinates) of the die on the LED wafer, and finally classifies the die as a bad grade according to the appearance information of the die.
Because the suspicious grains are classified as normal grains after passing through the first judgment standard, the AOI equipment transmits the information to the sorting equipment, and the suspicious grains are all sorted on the finished product square.
The method and the device for processing the LED crystal grains obtain the position information of the suspicious crystal grains while obtaining the pictures of the suspicious crystal grains, obtain the appearance information of the qualified crystal grains and the appearance information of the unqualified crystal grains according to the position information and the appearance parameter documents of the LED crystal grains, and classify the qualified crystal grains into good product grades, classify the unqualified crystal grains into defective product grades, so that the LED crystal grains on the finished product square piece are improved to be 100% of the qualified crystal grains.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (10)
1. An LED crystal grain appearance detection method is characterized by comprising the following steps:
carrying out optical detection on the LED crystal grains to obtain an appearance parameter document, wherein the appearance parameter document comprises the defect area proportion of the crystal grains;
dividing the LED crystal grains into first qualified crystal grains, first unqualified crystal grains and suspicious crystal grains according to the appearance parameter document, wherein the area proportion of the crystal grains of the suspicious crystal grains is within a preset range, the area proportion of the crystal grains of the first qualified crystal grains is smaller than the preset range, and the area proportion of the crystal grains of the first unqualified crystal grains is larger than the preset range;
acquiring a picture of suspicious grains, and judging the appearance defect types of the suspicious grains according to the picture of the suspicious grains, wherein the appearance defect types comprise epitaxial appearance defects and pollution appearance defects;
and dividing the suspicious crystal grains into second qualified crystal grains and second unqualified crystal grains according to the types of the appearance defects, wherein if the types of the appearance defects of the suspicious crystal grains are epitaxial appearance defects, the suspicious crystal grains are second unqualified crystal grains, if the types of the appearance defects of the suspicious crystal grains are polluted appearance defects, the suspicious crystal grains are second qualified crystal grains, the first qualified crystal grains and the second qualified crystal grains form qualified crystal grains, and the first unqualified crystal grains and the second unqualified crystal grains form unqualified crystal grains.
2. The LED die appearance inspection method according to claim 1, wherein the appearance parameter document further includes a die defect area, wherein a die defect area ratio is a die defect area/a die light-emitting area, the die light-emitting area is an area of an orthographic projection of the LED die on the light-emitting surface of the optical inspection apparatus, and the die defect area is a total area of an orthographic projection of the LED die on the optical inspection apparatus.
3. The LED die appearance inspection method according to claim 1, wherein the epitaxial appearance defects are appearance defects caused by epitaxial defects of the LED die, and the contaminated appearance defects are appearance defects caused by external contamination during the manufacturing process of the LED die.
4. The method for inspecting the appearance of an LED die according to claim 1, wherein the appearance defect comprises one or more of electrode dropping, light-emitting layer dropping, scratch, contaminant adhesion, dent and crack.
5. The LED die appearance inspection method of claim 1, wherein the method of separating the LED die into a first qualified die, a first unqualified die, and a suspect die comprises:
setting a first judgment standard, wherein if the area ratio of the crystal grain defects of the LED crystal grains is smaller than or equal to the first judgment standard, the LED crystal grains are primarily selected crystal grains, and if the area ratio of the crystal grain defects of the LED crystal grains is larger than the first judgment standard, the LED crystal grains are first unqualified crystal grains;
setting a second judgment standard, wherein if the area ratio of the crystal grain defect of the primary selected crystal grain is smaller than the second judgment standard, the primary selected crystal grain is a first qualified crystal grain, and if the area ratio of the crystal grain defect of the primary selected crystal grain is larger than or equal to the second judgment standard, the primary selected crystal grain is a suspicious crystal grain;
wherein, the area ratio of the crystal grain defect in the second judgment standard is smaller than that in the first judgment standard.
6. The LED die appearance inspection method according to claim 5, wherein the area ratio of die defects in the first criterion is 30% to 60%, and the area ratio of die defects in the second criterion is 10% to 40%.
7. The LED die appearance inspection method of claim 1, wherein said suspect die is scanned to generate a picture of said suspect die;
and transmitting the picture of the suspicious crystal grain to a display device, judging the type of the appearance defect of the suspicious crystal grain according to the picture of the suspicious crystal grain, and dividing the suspicious crystal grain into a second qualified crystal grain and a second unqualified crystal grain.
8. The LED die appearance inspection method of claim 1, further comprising:
acquiring the position information of the LED crystal grains, wherein the position information of the LED crystal grains comprises the position information of qualified crystal grains and the position information of unqualified crystal grains;
obtaining appearance information of qualified crystal grains and appearance information of unqualified crystal grains according to the position information and the appearance parameter document of the LED crystal grains;
and classifying the qualified crystal grains into good grade and classifying the unqualified crystal grains into bad grade according to the appearance information of the qualified crystal grains and the appearance information of the unqualified crystal grains.
9. The LED die appearance inspection method of claim 8, wherein the method of obtaining the location information of the LED die comprises:
carrying out optical detection on the LED crystal grains, and acquiring position information of the LED crystal grains while acquiring an appearance parameter document, wherein the position information of the LED crystal grains comprises the position information of a first qualified crystal grain, the position information of a first unqualified crystal grain and the position information of a suspicious crystal grain;
scanning the suspicious crystal grains to obtain the suspicious crystal grain picture and position information of the suspicious crystal grains, wherein the position information of the suspicious crystal grains comprises the position information of second qualified crystal grains and the position information of second unqualified crystal grains;
the position information of the first qualified crystal grains and the position information of the second qualified crystal grains form the position information of the qualified crystal grains, and the position information of the first unqualified crystal grains and the position information of the second unqualified crystal grains form the position information of the unqualified crystal grains.
10. The method for inspecting the appearance of the LED die according to claim 8 or 9, wherein the sorting device arranges the qualified die onto a finished product square according to the appearance information of the qualified die, and the appearance qualification rate of the LED die on the finished product square is 100%.
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