TWI694550B - Method and system for die testing - Google Patents

Abstract

The present invention provides a method and a system for testing a plurality of dies on a source wafer. The method includes: electrically connecting the positive terminal of each die with the negative terminal thereof using a conductive element so as to form a closed loop; providing a coil next to the plurality of dies; applying an alternating current to the coil so as to generate a change in magnetic flux across the coil, in which each closed loop generates an induced EMF that is higher than the threshold voltage of the die; determining whether an induced current flows through the die in each closed loop.

Description

Grain detection method and system

The invention relates to a die detection method and system, in particular to a die detection method and system for detecting die on a source wafer.

The traditional method of wafer inspection is to use a probe with a diameter of about 10 μm to contact the contacts on the die for electrical testing. After the die is inspected without defects, the subsequent processes such as cutting, picking and packaging are carried out. However, when the size of the die is small to be comparable to the size of the probe, such as a micro LED, it is difficult to perform electrical testing on the die using the detection methods of the prior art.

Therefore, in the prior art, the micro light emitting diode usually transfers the die to the panel through a micro transfer printing process after the die is cut on the source wafer, and cannot control the die defect rate of the panel . For this reason, the existing grain detection method is difficult to apply to small-scale grains, which makes the detection of small-scale grains difficult. Therefore, the existing grain detection methods still have insufficient and room for improvement.

In view of the above, the object of the present invention is to provide a die detection method and system in response to the shortcomings of the prior art, so that each die on the source wafer forms a loop, and by changing the magnetic flux, the crystal in each loop The granules are energized with induced current due to the induced electromotive force, thereby achieving the detection of the crystal grains.

One of the technical solutions provided by the embodiments of the present invention is to provide a source A method for detecting die on a wafer; wherein, a plurality of die are provided on the upper surface of the source wafer. The die detection method includes: electrically connecting the positive electrode and the negative electrode of each die with a conductive material to form a closed loop; setting the coil adjacent to a plurality of die; inputting an alternating voltage to the coil to change the magnetic flux of the coil, wherein Each closed loop generates an induced electromotive force according to the change of magnetic flux, and the peak value of the induced electromotive force is higher than the conduction voltage of the die; and it is determined whether the die in each closed loop is energized with an induced current in response to the induced electromotive force.

Another technical solution provided by an embodiment of the present invention is to provide a method for detecting a die on a source wafer; wherein, a plurality of dies are provided on the upper surface of the source wafer, and each two adjacent dies form a Die pairs, and each die pair includes a first die and a second die. The die detection method includes: forming a closed loop between the first die and the second die of each die pair through a conductive material. In each die pair, the positive electrode of the first die and the negative electrode of the second die are electrically connected And the negative electrode of the first die and the positive electrode of the second die are electrically connected to form a parallel connection in the closed loop; at least one coil is arranged adjacent to a plurality of die pairs; an AC voltage is input to the coil to cause the coil to generate Forward magnetic flux change and reverse magnetic flux change, where each closed loop generates a forward induced electromotive force according to the change in forward magnetic flux, the peak value of the forward induced electromotive force is higher than the conduction voltage of the first grain and smaller than that of the second grain Collapse voltage; each closed loop generates a reverse induced electromotive force according to the change of the reverse magnetic flux, the peak value of the reverse induced electromotive force is higher than the turn-on voltage of the second die and less than the collapse voltage of the first die; and judge each closed loop Whether each die in is responded to the induced electromotive force in the forward direction or the induced electromotive force in the reverse direction and is energized with an induced current.

Another technical solution provided by an embodiment of the present invention is to provide a die inspection system, which includes a source wafer and a coil. The upper surface of the source wafer is provided with a plurality of dies, and the positive electrode and the negative electrode of each die are electrically connected to form a closed loop. The coil is adjacent to a plurality of dies, and the coil is used to input an AC voltage to generate a change in magnetic flux. Among them, each closed loop generates an induced electromotive force according to the change of magnetic flux, and the peak value of the induced electromotive force is higher than the conduction voltage of the die.

Another technical solution provided by an embodiment of the present invention is to provide a die inspection system, which includes a source wafer and at least one coil. The upper surface of the source wafer is provided with a plurality of dies, wherein each two adjacent dies form a die pair, and each die pair includes a first die and a second die, the first die and the second die The two grains form a closed loop through the conductive material, and each grain is centered, the positive electrode of the first grain is electrically connected to the negative electrode of the second grain, and the negative electrode of the first grain is electrically connected to the positive electrode of the second grain Sexual connection to form a parallel in a closed loop. The coil is adjacent to a plurality of crystal grains, and is used to input an alternating voltage to generate a forward magnetic flux change and a reverse magnetic flux change. Each closed loop generates a forward induced electromotive force according to the change of the forward magnetic flux, wherein the peak value of the forward induced electromotive force is higher than the turn-on voltage of the first die and less than the breakdown voltage of the second die. Each closed loop generates a reverse induced electromotive force according to the change of the reverse magnetic flux, wherein the peak value of the reverse induced electromotive force is higher than the turn-on voltage of the second die and smaller than the breakdown voltage of the first die.

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and explanation only, and are not intended to limit the present invention.

Z‧‧‧grain detection system

1‧‧‧coil

11‧‧‧Wrap back structure

R‧‧‧coil range

2‧‧‧ source wafer

20‧‧‧upper surface

21‧‧‧ grain

21A‧‧‧First die

21B‧‧‧Second grain

210‧‧‧ die pair

22‧‧‧Connection

211‧‧‧Positive

212‧‧‧Negative

21’‧‧‧ grain projection

L‧‧‧Closed loop

3‧‧‧Display panel

i1‧‧‧forward current

i2‧‧‧Reverse current

i1’, i2’ ‧‧‧ induced current

C‧‧‧Conductive material

FIG. 1 shows a schematic diagram of a die inspection system according to a first embodiment of the invention.

FIG. 2 shows a flow chart of the grain inspection method of the first embodiment of the present invention.

FIG. 3 shows a schematic diagram of the induced current generated by the die of the first embodiment of the present invention.

FIG. 4 shows a schematic diagram of micro-transferring a die subjected to an induction current to a display panel in the die detection method according to the first embodiment of the present invention.

FIG. 5 shows a modified embodiment of the grain detection method of the first embodiment of the present invention.

FIG. 6 shows a schematic diagram of a die inspection system according to a second embodiment of the invention.

FIG. 7 shows a flow chart of the grain inspection method of the second embodiment of the present invention.

8 shows a schematic diagram of the induced current generated by the die pair of the second embodiment of the present invention Figure.

FIG. 9 is a schematic diagram showing the change of the alternating current and the induced electromotive force generated by the alternating voltage of the coil according to the second embodiment of the present invention with time.

FIG. 10 shows I-V characteristic curves of the first die and the second die of the second embodiment of the present invention.

FIG. 11 shows a schematic diagram of a modified embodiment of the die detection system according to the second embodiment of the present invention.

FIG. 12 shows a schematic diagram of another modified embodiment of the grain inspection system of the second embodiment of the present invention.

FIG. 13 shows a schematic top view of another modified embodiment of the die detection system of the second embodiment of the present invention.

14 shows a schematic side view of FIG. 13.

FIG. 15 shows a schematic side view of another modified embodiment of the grain inspection system of the second embodiment of the present invention.

16 shows a circuit diagram of another modified embodiment of the die detection system of the second embodiment of the present invention.

17 shows a circuit diagram of another modified embodiment of the die detection system of the second embodiment of the present invention.

The following describes the implementation of the disclosed grain detection method and system of the present invention through specific specific examples and FIG. 1 to FIG. 17. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. However, the content disclosed below is not intended to limit the protection scope of the present invention. Without departing from the spirit of the inventive concept, those skilled in the art can implement the present invention in other different embodiments based on different viewpoints and applications. In addition, prior It is stated that the drawings of the present invention are only schematic illustrations, and are not drawn according to actual sizes. In addition, although terms such as first, second, and third may be used herein to describe various elements, these elements should not be limited by these terms. These terms are mainly used to distinguish components.

First embodiment

The crystal detection system and method of the first embodiment of the present invention will be described below with reference to FIGS. 1 to 3. Please refer to FIG. 1, this embodiment provides a die inspection system Z, which has a coil 1 and a source wafer 2. The above-mentioned "source wafer" includes, but is not limited to, a silicon wafer for growing the die 21 thereon. The upper surface 20 of the source wafer 2 has a plurality of dies 21. In this embodiment, the die 21 is a micro LED (micro LED) die. However, the present invention is not limited thereto; in other embodiments, the die 21 may be other types of semiconductor die.

Please refer to FIG. 1 and FIG. 2. This embodiment provides a die detection method using the die detection system Z. The die detection method includes at least the following steps. Step S100: electrically connect the positive electrode 211 and the negative electrode 212 of each die 21 with a conductive material C to form a closed loop L; step S102: set the coil 1 adjacent to the plurality of die 21; step S104: match the coil 1 Input an AC voltage to cause the magnetic flux of the coil 1 to change, wherein each closed loop L generates an induced electromotive force according to the magnetic flux change, and the peak value of the induced electromotive force is higher than the conduction voltage of the die 21; and Step S106: determine each Whether the die 21 in the closed circuit L is energized with induced current due to the induced electromotive force.

As shown in the enlarged view of the die 21 on the right side of FIG. 1, in this embodiment, in step S100, a wire is used as the conductive material C to connect the positive electrode 211 and the negative electrode of the die 21, that is, the P electrode and the N electrode. However, the present invention does not limit the implementation of the conductive material. For example, in other examples, the conductive material may also be a conductive paint, a conductive film, or the like.

Further, as shown in FIG. 1, the coil 1 is arranged in parallel with the source wafer 2 in step S102, however, the present invention is not limited to this. In other modified embodiments, the coil 1 may also be provided Placed above, below, or on the upper surface 20 of the source wafer 2. More specifically, the location of the coil 1 is based on the principle that its magnetic field lines can pass through the closed loop L of the die 21 on the source wafer 2. In this way, when the coil 1 is energized with an AC voltage in step 104, each closed loop L can undergo a magnetic flux change to generate an induced electromotive force.

In step S104, the peak value of the induced electromotive force generated by the closed loop induction of the die 21 is higher than the conduction voltage of the die 21, so that the closed loop can generate an induced current i1', as shown in FIG. Specifically, because the induced electromotive force is proportional to the change in the number of coil gates and the magnetic flux, and the change in the magnetic flux of the current-carrying coil is related to the parameters such as the coil area, the current size, and the distance between the coil and the magnetic field, in this embodiment, the above parameters can be To obtain the required induced electromotive force value.

FIG. 3 shows a circuit diagram of the die 21 in which the coil 1 is supplied with alternating alternating forward current i1 and reverse current i2 due to the input of AC voltage AC. Here "forward" means clockwise, and "reverse" means counterclockwise. When the forward current i1 is in the coil 1, the magnetic field generated by the coil 1 vertically penetrates the plane; when the reverse current i2 is in the coil 1, the magnetic field generated by the coil 1 vertically exits the plane. When the current passing through the coil 1 is changed from the forward current i1 to the reverse current i2, the magnetic field of the coil 1 penetrating into the drawing first decreases gradually. At this time, the closed loop L of the die 21 on the source wafer 2 generates a forward direction The induced current i1' generates an induced magnetic field penetrating the graph to resist changes in magnetic flux. Then, when the direction of the current in the coil 1 changes, the reverse current i2 passes, and the reverse current i2 gradually increases. At this time, the coil 1 continues to generate the forward induced current i1' to counter the reverse current i2 generated through the figure magnetic field. When the current in the coil 1 is changed from the reverse current i2 to the forward current i1, the closed loop will generate a reverse induced electromotive force according to the principle of resisting the change of magnetic flux. However, due to the unidirectional current characteristics of the diode, the crystal grain 21 will not be turned on at this time.

Next, in step S106, in this embodiment, by determining whether the die 21 emits light to determine whether the die 21 is supplied with the induced current i1', it can further determine whether the electrical property of the die 21 is normal. It should be noted that, in other embodiments, other circuits can also be used to determine whether the circuit is The manner of conduction is to determine whether the induced current i1' passes through the die 21, and is not limited to the above.

Please refer to FIG. 4 and FIG. 5, in a variant embodiment, the die detection method of the present invention may further include step S300: passing the die 21 to which the induced current i1′ is passed through a micro-transfer step (micro- transfer printing) to a display panel 3. In this embodiment, the die 21 fed with the induced current i1' can be judged to be electrically normal, and in step S300, only the die 21 with normal electrical conductivity on the source wafer 2 (in FIG. 4, indicated by black squares) The die 21 whose electrical property is judged to be normal, and the white square represents the die 21 whose electrical property is judged to be abnormal) are transferred to the display panel 3. Therefore, compared with the conventional die inspection method, the die inspection system and method of the embodiments of the present invention can enable the die 21 to be inspected on the source wafer 2 to reduce the defect rate of subsequent products.

With the above technical solution, this embodiment connects the positive electrode 211 and the negative electrode 212 of each die 21 to form a closed circuit L, and uses the principle of electromagnetic induction to generate an induced electromotive force in the closed circuit, by observing whether the die 21 emits light It is further determined whether the induced current i1' passes through the die 21. In this way, the die inspection method and system provided in this embodiment can solve the problems of the conventional die inspection methods, so that small-scale die can be inspected on the source wafer 2. However, the detection method and system provided in this embodiment are not limited to the use of small-scale grain detection, which is described here.

Second embodiment

The grain detection system Z and the grain detection method provided by the second embodiment of the present invention are described below with reference to FIGS. 6 to 17. First, please refer to FIG. 6. The die inspection system Z provided in this embodiment includes at least one coil 1 and a source wafer 2. In this embodiment, of the plurality of dies 21 on the source wafer 2, each two adjacent dies 21 form a die pair 210, and each die pair 210 includes a first die 21A and a second die Grain 21B.

The grain detection method of the second embodiment is described below with reference to FIGS. 6 and 7. The method uses the grain detection system Z described above and includes at least the following steps. Step S200: through conduction The material forms a closed loop of the first die 21A and the second die 21B of each die pair 210, wherein the first die 21A in each die pair 210 has a positive electrode 211 and a negative electrode 212 of the second die 21B They are connected, and the negative electrode 212 is connected to the positive electrode 211 of the second die 21B, and the first die 21A and the second die 21B are connected in parallel. The enlarged view on the right side of FIG. 6 shows one of the die pairs 210 on the source wafer 2, wherein the first die 21A and the second die 21B are connected in parallel in the closed loop L through the wire W in a positive and negative manner .

Next, the die detection method of this embodiment further includes step S202: setting the coil 1 adjacent to the plurality of die pairs 210; step S204: inputting an AC voltage to the coil 1 to cause the coil 1 to generate forward magnetic flux changes and reverse magnetic flux Change, wherein each closed loop L generates a forward induced electromotive force according to the change of the forward magnetic flux, the peak value of the forward induced electromotive force is higher than the turn-on voltage of the first die 21A and less than the breakdown voltage of the second die 21B; A closed loop generates a reverse induced electromotive force according to the change of the reverse magnetic flux, the peak value of the reverse induced electromotive force is higher than the turn-on voltage of the second die 21B and less than the collapse voltage of the first die 21A; and Step S206: determine each Whether each die 21 in a closed loop L is energized with induced current due to the forward induced electromotive force or the reverse induced electromotive force.

FIG. 8 shows a schematic diagram of the induced current generated by the die pair 210. One of the differences between this embodiment and the first embodiment is that in the first embodiment, each die 21 forms a loop, and due to the unidirectional current of the diode, each die 21 forms Although the loop can induce a forward induced electromotive force and a reverse induced electromotive force in a unit cycle of AC voltage, only one direction of induced electromotive force can cause the loop to generate an induced current. In this embodiment, by connecting the first die 21A and the second die 21B in parallel with the positive and negative electrodes, the closed loop L formed by the first die 21A and the second die 21B can be positive The induced electromotive force and the reverse induced electromotive force generate a forward induced current and a reverse induced current, respectively, and the generated forward induced current and reverse induced current pass through the first die 21A and the second die 21B, respectively. In this way, you can make better use of communication The electrical energy of the voltage is used for electrical detection of the die 21.

Please refer to Figure 8 and Figure 9 together. In the embodiment of FIG. 8, the alternating voltage AC causes the forward current i1 and the reverse current i2 to alternately pass through the coil 1. When the forward current i1 and the reverse current i2 alternate, the magnetic flux of the coil 1 penetrating into the drawing first weakens, and after changing the current direction, the magnetic flux penetrating out of the drawing becomes stronger, forming a magnetic flux change φA as shown in FIG. 9. The closed loop L accordingly generates a forward induced current i1' to resist the decrease in the magnetic flux penetrating into the drawing and the increase in the magnetic flux penetrating the drawing to compensate for the magnetic flux change φA. Since the direction of the positive electrode 211 to the negative electrode 212 of the first die 21A coincides with the direction of the forward induced current i1', the first die 21A is energized with the induced current i1'. Conversely, when the reverse current i2 turns into the forward current i1, the geomagnetic flux of the coil 1 passing through the drawing first weakens. Then, after changing the direction of the current, the geomagnetic flux penetrating into the drawing becomes stronger, forming The magnetic flux changes by φB. At this time, the closed loop L correspondingly generates a reverse induced current i2' to resist the decrease of the magnetic flux passing through the plane and the increase of the magnetic flux penetrating into the plane, offsetting the change in magnetic flux φA, and due to the positive electrode 211 of the second die 21B The direction to the negative electrode 212 is consistent with the direction of the reverse induced current i2', and the reverse induced current i2' passes through the second die 21B.

Please refer to FIG. 10, which shows I-V characteristic curves of the first die 21A and the second die 21B. In step S204, in this embodiment, by adjusting the parameters related to the change in magnetic flux such as the number of coil gates, the coil shape, the distance between the source wafer and the coil, and the AC voltage, the forward induced electromotive force peak is higher than the conduction of the first die 21A The voltage V1 is less than the collapse voltage V2 of the second die 21B, and the peak value of the reverse induced electromotive force corresponding to the reverse induced current i2' is higher than the turn-on voltage V3 of the second die 21B and less than the collapse voltage V4 of the first die. It should be noted that the induced electromotive force value here refers to an absolute value, and is not vectorial. In this way, by controlling the induced electromotive force, the embodiment of the present invention can enable the die 21 to be detected in the closed loop to be passed through the induced currents i1', í2', while also protecting the die 21 from damage due to the collapse effect.

In this embodiment, step S206 is by observing the first crystal 21A and the second crystal Whether the grain 21B is lit to determine whether the induced currents i1' and í2' are generated. If it is determined that the induced current is generated, it can be determined that the grain 21 is electrically normal. In addition, whether the die 21 has a defect can also be determined by whether the die 21 is shiny, for example, whether it flashes or whether the brightness is normal. In addition, it should be emphasized that the present invention is not limited to determining whether the induced current is generated by observing whether the crystal grain emits light. In other embodiments, when the die 21 is a die other than the light emitting diode, it can also be determined whether the die is passed by the induced current through other methods, such as using a galvanometer to determine the generation of the induced current, or using a magnetic field to sense The sensor senses the generation of the induced magnetic field.

See Figure 11. In this embodiment, the position where the coil 1 is provided is not limited to that shown in FIG. 6. In other modified embodiments of the present invention, the coil 1 may also be disposed above or below the source wafer 2 (the lower side in FIG. 11 is an example), wherein the coil 1 is preferably substantially parallel to the upper surface 20 of the source wafer 2 , And the vertical projection 21 ′ formed by the plurality of die pairs 210 on the source wafer 2 on the plane of the coil 1 falls within the range R defined by the coil 1. Specifically, as described above, the plane refers to the uppermost circle of the coil 1 surrounding the defined circular plane, and the range R defined by the coil 1 refers to the range of the circular plane of the coil 1.

In another modified embodiment, the coil 1 may also be disposed on the upper surface 20 of the source wafer 2 as shown in FIG. 12, and the die pair 210 is located within the range R defined by the coil 1. It should be noted that the installation position of the coil 1 is not limited to the above-mentioned example, as long as the magnetic force lines of the coil 1 can pass through the closed circuit formed by the crystal grains 21,

The embodiments above are all described with an example in which one coil 1 is provided, however, the invention is not limited thereto. Please refer to FIGS. 13 and 14, wherein FIG. 13 is a top view of a die pair 210 according to a variant embodiment of the invention, and FIG. 14 is a side view of FIG. 13. In a variant embodiment of the invention, a coil 1 may be provided on the upper surface 20 for each die pair 210, wherein the coil 1 forms a wrap-around structure 11 with the die pair 210 as the center. For example, in the embodiment of FIG. 13, the positive electrode 211 of the first die 21A and the negative electrode 212 of the second die 21B are connected to point A of the closed loop L, and the first die 21A The negative electrode 212 and the positive electrode 211 of the second die 21B are connected to point B of the closed circuit L, and point A and point B are connected by a wire W so that the first die 21A and the second die are connected in parallel, and the coil 1 forms a The rewind structure 11 surrounding the first die 21A and the second die 21B. In addition, in this embodiment, both ends of the coil 1 are connected to points A and B, respectively, so that the coil 1 and the closed loop L form a parallel connection. This connection method can improve the manufacturing efficiency of the closed loop L and the coil 1, however, the present invention is not limited to this.

Please refer to FIG. 14. In this modified embodiment, the coil 1 is connected to the connection portion 22 of the first die 21A and the second die 21B. The connecting portion 22 is preferably formed in the manufacturing process of the micro-luminescent diode to connect the die 21 and the source before the micro-emitting diode die 21 is transferred to the display panel 3 shown in FIG. 4 in a large amount Wafer 2. In the process of transferring the crystal grains 21 in a large amount, the connecting portion 22 is broken and broken, so that the crystal grains 21 are released to be transferred. In addition, unlike the previous embodiment in which the conductive material C is implemented by wires, in this embodiment, the first die 21A and the second die 21B are electrically connected by a conductive substance.

In the modified embodiments of FIGS. 13 and 14, the coil 1 does not overlap with the first die 21A and the second die 21B in the direction perpendicular to the source wafer 2, however, the present invention is not limited to this. In another modified embodiment, as shown in FIG. 15, the present invention may also arrange the coil 1 between the source wafer 2 and the die pair 210 so that the die pair 210 and the coil 1 are perpendicular to the source wafer 2 At least partially overlap in the direction of to increase the space utilization of the source wafer 2 surface.

In addition to connecting each die pair 210 on the source wafer 2 with positive and negative electrodes to form a parallel closed loop as shown in FIG. 6, in another variation of the present invention, multiple crystals with positive and negative electrodes can also be connected The pair of grains 210 penetrates through the conductive material to form multiple closed loops of the pair of grains 210 connected in parallel, as shown in FIG. 16. Furthermore, in another modified embodiment, the closed loops in which the multiple pairs of die pairs 210 are connected in parallel may be further connected in parallel to each other, as shown in FIG. 17. Implementing the grain detection method of the embodiment of the present invention with the closed loop structure of FIG. 16 or FIG. 17 can increase the detection efficiency. This is because in the case where multiple pairs of die pairs 210 are connected in parallel, the forward induced current i1' and the reverse induced current i2' can All the first die 21A or the second die 21B in one closed loop L are passed through at a time.

In summary, the die detection method and system provided by the embodiments of the present invention form a closed loop L by "forming the first die 21A and the second die 21B of each die pair 210 through a conductive material. In the pair 210, the positive electrode 211 of the first die 21A and the negative electrode 212 of the second die 21B are electrically connected, and the negative electrode 212 of the first die 21A and the positive electrode 211 of the second die 21B are electrically connected to seal Parallel formation in the loop L, "input of an AC voltage to the coil 1" and "the peak value of the forward induced electromotive force is higher than the conduction voltage V1 of the first die 21A and less than the breakdown voltage V2 of the second die 21B, reverse induction The peak value of the electromotive force is higher than the turn-on voltage V3 of the second die 21B and less than the breakdown voltage V4 of the first die 21A" to "determine whether each die 21 in each closed loop L responds to forward sensing The electromotive force or the reverse induced electromotive force is passed through induced current."

In this way, the die detection method and system Z provided by the embodiment of the present invention can enable the die 21 to be detected on the source wafer 2 to solve the conventional problem that the small-scale die 21 cannot be carried out before the massive transfer of the die 21 Problems detected. In addition, by making the crystal grains 21 form a parallel structure in the closed loop L, the embodiment of the present invention can further improve the detection efficiency.

The content disclosed above is only a preferred and feasible embodiment of the present invention, and therefore does not limit the scope of the patent application of the present invention, so any technical changes made by using the description and drawings of the present invention fall into the application of the present invention. Within the scope of the patent.

This manual specifies the representative diagram as a flow chart, so there is no symbol for a simple explanation.

Claims (19)

A method for detecting dies on a source wafer, wherein a plurality of dies are provided on an upper surface of the source wafer, the method includes: electrically connecting the positive electrode and the negative electrode of each die with a conductive material Connected to form a closed loop; setting a coil adjacent to the plurality of dies; inputting an AC voltage to the coil to cause the coil to produce a change in magnetic flux, wherein each closed loop generates a Induced electromotive force, the peak value of the induced electromotive force is higher than the conduction voltage of the die; and it is determined whether the die in each closed loop is energized with an induced current due to the induced electromotive force. A method for detecting crystal grains on a source wafer, wherein a plurality of crystal grains are provided on an upper surface of the source wafer, and every two adjacent crystal grains form a crystal grain pair, and each crystal grain The particle pair includes a first die and a second die. The method includes: forming a closed loop between the first die and the second die of each die pair through a conductive material, wherein each In the center of the die, the positive electrode of the first die is electrically connected to the negative electrode of the second die, and the negative electrode of the first die is electrically connected to the positive electrode of the second die in the closed loop Parallel formation; at least one coil is adjacent to the plurality of die pairs; an AC voltage is input to the coil to cause the coil to produce a forward magnetic flux change and a reverse magnetic flux change, wherein each closed loop is based on The forward magnetic flux changes to generate a forward induced electromotive force, wherein the peak value of the forward induced electromotive force is higher than the turn-on voltage of the first die and less than the breakdown voltage of the second die; each of the closed loops is based on the The reverse magnetic flux changes to generate a reverse induced electromotive force, where the reverse sense The peak value of the electromotive force is higher than the turn-on voltage of the second die and less than the breakdown voltage of the first die; and it is determined whether each of the die in each closed loop should be induced by the electromotive force in the forward direction or the reverse direction The induced electromotive force is passed through an induced current. The method according to claim 2, wherein after determining whether each of the dies in each of the closed loops is energized with the induced current due to the forward induced electromotive force or the reverse induced electromotive force, further The method includes: transferring the die passed by the induced current to a display panel through a micro-transfer printing process. The method according to claim 2, wherein the step of arranging the coil adjacent to the plurality of die pairs further comprises: providing a coil corresponding to each die pair on the upper surface, each of the coils The pair of crystal grains is centered to form a wrap-around structure. The method according to claim 4, wherein each of the coils is connected in parallel with the corresponding die pair. The method of claim 2, wherein the step of arranging the coil adjacent to the plurality of die pairs further comprises: providing a coil corresponding to each die pair on the upper surface, the coil being perpendicular to The direction of the upper surface is located between the source wafer and the corresponding die pair, and each of the die pair and the corresponding coil at least partially overlap in a direction perpendicular to the source wafer. The method of claim 2, wherein the step of arranging the coil adjacent to the plurality of die pairs further comprises: arranging a coil on a plane parallel to the upper surface, the plurality of die pairs The projection of the plane falls within a range defined by the coil. The method according to claim 2, wherein the step of arranging the coil adjacent to the plurality of die pairs further comprises: setting a coil on the upper surface, the plurality of die pairs located in the coil A range. The method according to claim 2, wherein the first die and the second die of each die pair form the closed loop through the conductive material, wherein each of the die pairs is centered, the The positive electrode of the first die is electrically connected to the negative electrode of the second die, and the negative electrode of the first die is electrically connected to the positive electrode of the second die to form a parallel step in the closed loop, The method further includes: connecting a plurality of the grain pairs in parallel with each other by the conductive material to form the closed loop. The method according to claim 9, wherein in the step of connecting the plurality of crystal grain pairs in parallel with each other to form the closed loop through the conductive material, the method further includes: connecting the plurality of crystal grains in parallel with each other through the conductive material The loops formed by the particle pairs are then connected in parallel to each other to form the closed loop. A die detection system includes: a source wafer, a plurality of dies are provided on an upper surface of the source wafer, and the positive electrode and the negative electrode of each die are electrically connected to form a closed loop; and a A coil adjacent to the plurality of dies, the coil is used to input an alternating voltage to generate a magnetic flux change, wherein each closed loop generates an induced electromotive force according to the magnetic flux change, the peak value of the induced electromotive force Higher than the turn-on voltage of the die. A die detection system, comprising: a source wafer, a plurality of dies are provided on an upper surface of the source wafer, wherein each two adjacent dies form a die pair, and each die The grain pair includes a first grain and a first Two die, the first die and the second die form a closed loop through a conductive material, and each of the die is centered, the positive electrode of the first die and the negative electrode of the second die are electrically Connected, and the negative electrode of the first die and the positive electrode of the second die are electrically connected to form a parallel in the closed loop; and at least one coil, the at least one coil is adjacent to the plurality of die, the coil is It is used to input an AC voltage to generate a forward magnetic flux change and a reverse magnetic flux change, wherein each closed loop generates a forward induced electromotive force according to the forward magnetic flux change, wherein the peak value of the positive induced electromotive force Higher than the conduction voltage of the first die and smaller than the breakdown voltage of the second die; each closed loop generates a back-induced electromotive force according to the change of the reverse magnetic flux, wherein the peak value of the back-induced electromotive force is high The turn-on voltage of the second die is less than the breakdown voltage of the first die. The die inspection system according to claim 12, wherein each of the coils is disposed on the upper surface and corresponds to each of the die pairs, and each of the coils forms a wrap-around structure with the die pairs as the center. The die inspection system according to claim 12, wherein each of the coils forms a parallel connection with the corresponding die pair. The die inspection system according to claim 14, wherein each of the coils is disposed on the upper surface and corresponds to each of the die pairs, and the coil is located on the source wafer and in a direction perpendicular to the upper surface Between the corresponding die pairs, and each of the die pairs and the corresponding coil at least partially overlap in a direction perpendicular to the source wafer. The die inspection system according to claim 12, wherein one of the coils defines a plane parallel to the upper surface, and the projection of the plurality of die pairs on the plane lies within a range defined by the coil. The die inspection system according to claim 12, wherein one of the coils is disposed on the On the surface, the plurality of die pairs are located within a range defined by one of the coils. The die inspection system according to claim 12, wherein each of the closed loops includes a plurality of the die pairs connected in parallel with each other through the conductive material. The grain inspection system according to claim 18, wherein each of the closed loops includes a plurality of loops formed by the pair of grains connected in parallel with each other by the conductive material, and the plurality of loops are connected in parallel with each other by the conductive material.

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