CN117525259A - LED chip and LED chip die bonding method - Google Patents

LED chip and LED chip die bonding method Download PDF

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Publication number
CN117525259A
CN117525259A CN202311580704.6A CN202311580704A CN117525259A CN 117525259 A CN117525259 A CN 117525259A CN 202311580704 A CN202311580704 A CN 202311580704A CN 117525259 A CN117525259 A CN 117525259A
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China
Prior art keywords
electrode
bonding pad
led chip
communication
bonding
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卢敬权
李泽祺
殷淑仪
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Dongguan Sino Crystal Semiconductor Co ltd
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Dongguan Sino Crystal Semiconductor Co ltd
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Priority to CN202311580704.6A priority Critical patent/CN117525259A/en
Publication of CN117525259A publication Critical patent/CN117525259A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0093—Wafer bonding; Removal of the growth substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Led Device Packages (AREA)

Abstract

The invention discloses an LED chip, wherein a P electrode, an N electrode and a communication electrode are respectively formed on the first surface of an electrode formed by the LED chip, the P electrode and the N electrode are connected together by the communication electrode, and the melting point of the communication electrode is higher than that of the N electrode and the P electrode. The invention also discloses a die bonding method of the LED chip, which comprises the steps of transferring the LED chip to a circuit substrate, bonding an electrode of the LED chip with a bonding pad of the circuit substrate, electrifying the bonding pad of the circuit substrate, enabling the electrode of the LED chip to be melted on the bonding pad in a short circuit manner to form a new electrode until the connected electrode is melted, and cooling to finish die bonding. Compared with the prior art, the invention has reliable control and high efficiency.

Description

LED chip and LED chip die bonding method
Technical Field
The invention relates to a display technology, in particular to a die bonding method of an LED chip.
Background
With the progress of display technology, the market is increasingly not full of disadvantages of low contrast, low color gamut, low response speed, and the like of LCDs (Liquid Crystal Display, liquid crystal displays), and disadvantages of burn-in, heavy particle feel, color shift, poor light comfort, and the like of OLEDs (Organic Light EmittingDisplay, organic light emitting displays). As the next generation display technology, the Micro LED display technology has the advantages of high contrast ratio, high color gamut, high response speed, ultrahigh resolution, long service life and the like, and has the advantages of LCD and OLED and has no defects. Micro LED also has the advantages of flexible display and low energy consumption, and is known as an ultimate display technology.
Millions of Micro-scale LEDs need to be transferred to a back plate for manufacturing a Micro LED display, and then die bonding is performed. The most common die bonding method in the prior art is to package an LED chip on an LED package body and then weld the LED package body on a circuit substrate, which not only has complicated steps, but also makes a display thicker and has poor heat dissipation.
For this reason, in chinese patent CN113594339a, a method for manufacturing a display panel is disclosed, in which an LED chip is transferred onto a bonding pad of a substrate, and then an alternating magnetic field is applied to melt-bond a connection electrode and a corresponding bonding pad, and an eddy current effect is generated in the connection electrode and the corresponding bonding pad by using the alternating magnetic field, so that the connection electrode and the corresponding bonding pad are heated and melted, thereby realizing the melt-bonding, and further realizing the rapid connection between the LED chip and the substrate. However, the LED die bonding method is generally die bonding in batches, so that it is difficult to ensure that all LED chips are in the completely same uniform alternating magnetic field, it is difficult to ensure the uniformity of melting and heating of all LED chips on the whole substrate, and it is also difficult to control the melting temperature of the connection electrodes and bonding pads of the LED chips, and the die bonding effect is poor. Furthermore, since the whole substrate is required to be placed in an alternating magnetic field together with the LED chip, other conductive circuits on the substrate are affected by the eddy current effect at the same time, and other metal parts without die bonding, especially the electric connection circuits arranged on the back of the substrate far away from the bonding pad, can be greatly damaged.
Therefore, a die bonding method for controlling the LED chip reliably and efficiently is urgently needed.
Disclosure of Invention
The invention aims to provide an LED chip and a die bonding method for die bonding the LED chip, wherein the die bonding method is reliable in control and high in efficiency.
In order to achieve the above object, the present invention discloses an LED chip, wherein a P electrode, an N electrode, and a communication electrode are formed on a first surface of an electrode forming the LED chip, respectively, the communication electrode connects the P electrode and the N electrode together, and a melting point of the communication electrode is higher than melting points of the N electrode and the P electrode.
Preferably, the area and width of the communication electrode are smaller than the area and width of the P electrode and the N electrode.
Preferably, the communication electrode is in a strip shape, the P electrode and the N electrode are arranged at intervals along a first direction, a length direction of the communication electrode arranged along the first direction is greater than a width direction of the communication electrode extending along a second direction, a width of the communication electrode is smaller than a width of the P electrode and the N electrode along the second direction, and the first direction is perpendicular to the second direction. So that the communicating electrode can be disconnected in time after being heated to the melting point.
Preferably, the two ends of the communication electrode extend to the P electrode and the N electrode respectively and are covered by the P electrode and the N electrode, so that the P electrode or the N electrode is accidentally disconnected from the communication electrode after being melted during die bonding, and the die bonding effect of the LED chip is affected.
Preferably, the LED chip further comprises an epitaxial layer, wherein the epitaxial layer comprises a P-type layer, a light-emitting layer and an N-type layer, the P electrode is communicated with the P-type layer, and the N electrode is communicated with the N-type layer.
Optionally, the LED chip further includes a reflective layer located outside the epitaxial layer and a substrate located on the second surface of the LED chip, a buffer layer and an intrinsic layer are disposed between the substrate and the epitaxial layer, and the first surface and the second surface of the LED chip are disposed opposite to each other.
The invention also discloses a die bonding method of the LED chip, which comprises the following steps: step 1, providing a plurality of LED chips as described above; providing a circuit substrate, wherein the circuit substrate is provided with a plurality of groups of bonding pads, and each group of bonding pads is provided with a first bonding pad and a second bonding pad; step 2, transferring a plurality of LED chips to the circuit substrate, and enabling the P electrode and the N electrode of the LED chips to be respectively and oppositely attached to a first bonding pad and a second bonding pad on the circuit substrate; and 3, respectively connecting the first bonding pad and the second bonding pad with positive and negative electricity so as to enable the N electrode and the P electrode to be in short circuit through the communication electrode, enabling the N electrode and the P electrode to be in short circuit and generate heat along with the short circuit, melting the N electrode to the first bonding pad and forming a first electrode with the first bonding pad after reaching a melting point, and melting the P electrode to the second bonding pad and forming a second electrode with the second bonding pad until the communication electrode reaches the melting point and fuses.
Preferably, the melting point of the communication electrode is higher than the melting points of the first bonding pad and the second bonding pad, so that the N electrode, the P electrode, the first bonding pad and the second bonding pad are melted after being heated by short circuit of the connection electrode, the first bonding pad and the N electrode are fused together to form a first electrode, and the second bonding pad and the P electrode are fused together to form a second electrode.
Preferably, the melting point of the communication electrode is lower than the melting points of the first pad and the second pad.
Preferably, the melting point of the communication electrode is equal to the melting points of the first bonding pad and the second bonding pad, and in the step 3, when the communication electrode reaches the melting point and fuses, the first bonding pad melts and the second bonding pad melts.
Preferably, the first bonding pad and the second bonding pad are respectively connected with positive and negative electricity specifically: and continuously electrifying the first bonding pad and the second bonding pad for a preset time.
Preferably, the first bonding pad and the second bonding pad are respectively connected with positive and negative electricity specifically: detecting the on-off of the communication electrodes after the first bonding pad and the second bonding pad are continuously electrified, and stopping supplying power to the first bonding pad and the second bonding pad when the fusing proportion of the communication electrodes of a plurality of LED chips arranged on the circuit substrate is larger than a preset value and the electrifying time is longer than the preset time.
More preferably, detecting the on-off state of the communication electrode specifically includes: detecting the power supply current between the first bonding pad and the second bonding pad, and judging that the corresponding communication electrode is fused when the current of the power supply end is smaller than a preset value.
More preferably, detecting the on-off state of the communication electrode specifically includes: and detecting whether the LED chip is lighted or not, and judging that a communication electrode of the LED chip is fused when the LED chip is lighted.
Preferably, the die bonding method of the LED chip further comprises step 4: and waiting for the circuit substrate and the LED chips to be cooled, and removing the LED chips which are failed to be welded on the circuit substrate after the temperature is reduced.
Preferably, after the communicating electrode is subsequently melted down to the melting point, a portion of the communicating electrode is fused by the first electrode, and a portion of the communicating electrode is fused by the second electrode.
Preferably, in the step 3, the first pad and the second pad are respectively connected with positive and negative electricity with a preset voltage and last for a preset time.
Compared with the prior art, the LED chip has the advantages that the connecting electrode with the melting point higher than that of the N electrode and the P electrode is connected between the N electrode and the P electrode of the traditional LED chip, so that after the LED chip is transferred to the circuit substrate, the circuit substrate is directly electrified, the N electrode and the P electrode are in short circuit and are fused to the corresponding bonding pad through the short circuit of the connecting electrode under the condition of high current, the die bonding of the LED chip is completed, a special welding head and welding flux are not needed, the circuit substrate is electrified, the operation is simple and the efficiency is high, the short circuit heating part is limited at the N electrode, the P electrode, the first bonding pad and the second bonding pad of the LED chip, the conductive circuit on the back surface of the circuit substrate or other parts is not damaged, the die bonding effect is good, the heating efficiency of each LED chip can be accurately controlled through the electrified voltage and time, and the uniformity of welding connection is high.
Drawings
Fig. 1 is a structural diagram of an LED chip in embodiment 1.
Fig. 2 is a top view of the LED chip in embodiment 1.
Fig. 3 is a structural diagram of an LED chip in embodiment 2.
Fig. 4 is a structural diagram of the transfer of the LED chip onto the circuit substrate.
Fig. 5 is a flowchart of a die bonding method of the LED chip in embodiment 3.
Fig. 6 is a diagram showing removal of an LED chip failed in die bonding from a circuit substrate in example 3.
Fig. 7 is a flowchart of a die bonding method of the LED chip in embodiment 4.
Fig. 8 is a diagram showing removal of an LED chip failed in die bonding from a circuit substrate in example 4.
Fig. 9 is a flowchart of a die bonding method of the LED chip in embodiment 5.
Detailed Description
In order to describe the technical content, the constructional features, the achieved objects and effects of the present invention in detail, the following description is made in connection with the embodiments and the accompanying drawings.
The invention discloses an LED chip 10 and also discloses a method for manufacturing a display panel, wherein a plurality of LED chips 10 are die-bonded on a circuit substrate 40 in batches. The LED chip used in this embodiment is a Micro LED or a Mini LED.
Example 1:
referring to fig. 1, the invention discloses an LED chip 10, a P electrode 21, an N electrode 22 and a communication electrode 23 are arranged on a first surface of the LED chip 10 forming an electrode, the communication electrode 23 connects the P electrode 21 and the N electrode 22 together, and the melting point of the communication electrode 23 is higher than that of the N electrode 22 and the P electrode 21. The P electrode 21, the N electrode 22, and the communication electrode 23 are all metal electrodes.
Referring to fig. 2, the area and width of the communication electrode 23 are smaller than those of the P electrode 21 and the N electrode 22. Specifically, the communication electrode 23 is in a strip shape, the P electrode 21 and the N electrode 22 are arranged at intervals along a first direction, a length direction of the communication electrode 23 arranged along the first direction is greater than a width direction of the communication electrode 23 extending along a second direction, a width of the communication electrode 23 is smaller than a width of the P electrode 21 and the N electrode 22 along the second direction, and the first direction is perpendicular to the second direction.
Referring to fig. 1, the LED chip 10 includes an epitaxial layer including a P-type layer 11, a light emitting layer 12, and an N-type layer 13, the P-electrode 21 communicates with the P-type layer 11, and the N-electrode 22 communicates with the N-type layer 13. In this embodiment, the N-type layer 13 is N-type gallium nitride, the light emitting layer 12 is InGaN/GaN multiple quantum well, and the P-type layer 11 is P-type gallium nitride. The P electrode 21 may be directly formed on the P-type layer 11. The specific structure of the LED chip epitaxial layer is common knowledge in the art, and will not be described in detail herein.
Preferably, the LED chip 10 further comprises a reflective layer 14 on one side of the epitaxial layer. In this embodiment, the reflective layer 14 is adjacent to the P electrode 21, the N electrode 22, and the communication electrode 23 with respect to the epitaxial layer. Specifically, in the present embodiment, the P electrode 21 communicates with the P-type layer 11 and is formed on the reflective layer 14, the N electrode 22 communicates with the N-type layer 13 and is formed on the reflective layer 14, and the communication electrode 23 is formed on the reflective layer 14 and communicates with the N electrode 22 and the P electrode 21.
Optionally, the second surface of the LED chip 10 is further provided with a substrate 31, a buffer layer and an intrinsic layer 32 are disposed between the substrate 31 and the epitaxial layer, and the first surface and the second surface of the LED chip are disposed opposite to each other. Wherein the substrate 31 is sapphire or silicon carbide or the like. The reflective layer 14 is a distributed Bragg reflective layer (Distributed Bragg reflection layer, DBR) made of SiO 2 /Ta 2 O 5 And the like.
Preferably, a transparent conductive layer is further disposed between the reflective layer 14 and the P-type layer 11.
Example 2:
referring to fig. 3, unlike embodiment 1, both ends of the communication electrode 23a extend to the P electrode 21 and the N electrode 22, respectively, and are partially covered by the P electrode 21 and the N electrode 22. This arrangement ensures that after the P electrode 21 and the N electrode 22 are melted into balls after the short circuit, the electrical connection of the P electrode 21 and the N electrode 22 with the communication electrode 23a, respectively, is ensured to maintain the short circuit state.
Wherein both ends of the communication electrode 23a extend to the middle of the P electrode 21 and the N electrode 22, respectively. Of course, both ends of the communication electrode 23a may extend to the outer edges of the P electrode 21 and the N electrode 22.
Example 3:
referring to fig. 4 and 5, the invention also discloses a die bonding method of the LED chip 10, which includes steps S11 to S13. Wherein the melting point of the communication electrode 23a is lower than the melting points of the first pad 41 and the second pad 42.
In step S11, a plurality of LED chips 10 as described above are provided, and a circuit substrate 40 is provided, the front surface of the circuit substrate 40 having a plurality of sets of pads, each set of pads having a first pad 41 and a second pad 42, to form a corresponding pad array on the circuit substrate 40. The first pad 41 and the second pad 42 are both metal pads. The LED chip 10 may be the LED chip 10 in embodiment 1, or may be the LED chip 10 in embodiment 2, and this embodiment is exemplified by the LED chip 10 in embodiment 2.
In step S12, referring to fig. 5 (a), a plurality of LED chips 10 are transferred onto the circuit board 40, and the P-electrode 21 and the N-electrode 22 of the LED chip 10 are respectively bonded to the first bonding pad 41 and the second bonding pad 42 on the circuit board 40.
In step S13, the first bonding pad 41 and the second bonding pad 42 are respectively connected to positive and negative electricity, so that the N electrode 22 and the P electrode 21 are short-circuited by the communication electrode 23a, and referring to (b) in fig. 5, the N electrode 22 and the P electrode 21 are short-circuited to generate heat, and after reaching the melting point, the N electrode 22 is melted onto the second bonding pad 42 and forms the second electrode 52 with the second bonding pad 42, and the P electrode 21 is melted onto the first bonding pad 41 and forms the first electrode 51 with the first bonding pad 41. Referring to fig. 5 (c), the energization is continued, and the temperature at the short circuit continues to rise until the communication electrode 23a reaches the melting point and fuses, at which time the short-circuited current path is naturally opened.
Wherein, the back and/or front of the circuit substrate 40 is provided with a driving line electrically connected with the first pad 41 and the second pad 42, and the driving line is powered to power the first pad 41 and the second pad 42 so as to be connected with the corresponding positive and negative electricity.
In this embodiment, the second pad 42 electrically connected to the N electrode 22 is negatively charged, and the first pad 41 electrically connected to the P electrode 21 is positively charged. Of course, the second pad 42 electrically connected to the N electrode 22 may be positively charged, and the first pad 41 electrically connected to the P electrode 21 may be negatively charged.
The voltage of the positive and negative electricity is set according to the actual requirement, and the time of energizing the first bonding pad 41 and the second bonding pad 42 is preset time set by the actual requirement, or is determined according to the current detected melting condition of the P electrode 21 and the N electrode 22 and the on-off of the communication electrode 23a, or is determined according to the current light emitting condition of the LED chip. When it is detected that the current supplied is drastically reduced and reduced below a preset value, for example, it is judged that the communication electrode 23a is fused and power supply is stopped, and in this embodiment, power is supplied uniformly to all the pad groups. Of course, in another embodiment, the pad group is divided into a plurality of areas (e.g., five, ten, etc.), each area is independently powered and the current level is detected to determine whether all of the communication electrodes 23a of the current area are fused, and power is cut off when all of the communication electrodes 23a of the current area are fused. Even, in an embodiment, each of the pad groups is independently supplied with power, and the magnitude of the current between the pad groups is detected, and when the current is smaller than a preset value, it is judged that all the communication electrodes 23a of the current region are fused.
In another embodiment, the light emitting condition of each LED chip is detected by the camera, particularly, when the first bonding pad 41 is positively charged and the second bonding pad 42 is negatively charged, when the communication electrode 23a is fused, the voltage drop is located on the pn junction of the LED chip, and when the voltage drop is greater than the turn-on voltage of the LED chip 10, the LED chip 10 emits light. When the LED chips of a predetermined proportion or more are lighted on the front circuit substrate, it is judged that the communication electrode 23a is fused and power supply to the pad group is stopped, for example, when 95% of the LED chips are lighted and the power supply time is continued for a predetermined time or more, it is judged that the communication electrode 23a is fused and power supply to the pad group is stopped.
Preferably, referring to fig. 6, the die bonding method of the led chip 10 further includes step S14: and waiting for the cooling of the circuit substrate 40 and the LED chips 10, and removing the LED chips 10 which fail to be soldered on the circuit substrate 40 after cooling. The circuit substrate 40 and the LED chip 10 may be cooled in a cooling environment, or the cooling gas may be sprayed directly to the die bonding site for active cooling, or the cooling gas may be naturally cooled at normal temperature. Wherein the transfer head 60 is used to remove the LED chip 10 that failed die attach.
Wherein, after the communication electrode 23a is subsequently melted down to the melting point, a part of the communication electrode 23a is fused to the first electrode 51, and a part of the communication electrode 23a is fused to the second electrode 52. Of course, after the connection electrode 23a subsequently reaches the melting point to melt, the connection electrode 23a may be completely fused to the first electrode 51 or the second electrode 52, or after the connection electrode 23a is disconnected, there may remain a part of the residue between the first electrode 51 and the second electrode 52.
Of course, since the first electrode 51 and the second electrode 52 are in a molten state when the communication electrode 23a is melted, the melted communication electrode 23a will be strongly adsorbed, so that most or even all of the material of the communication electrode 23a is fused into the first electrode 51 and/or the second electrode 52.
Example 4:
unlike embodiment 3, in the present embodiment, the melting point of the communication electrode 23a is higher than the melting points of the first pad 41 and the second pad 42. In this embodiment, the die bonding method of the LED chip 10 includes steps S11 to S13.
In step S11, a plurality of LED chips 10 as described above are provided, and a circuit substrate 40 is provided, the first side of the circuit substrate 40 having a plurality of sets of pads, each set of pads having a first pad 41 and a second pad 42. The first pad 41 and the second pad 42 are both metal pads.
In step S12, referring to fig. 7 (a), a plurality of LED chips 10 are transferred onto the circuit board 40, and the P-electrode 21 and the N-electrode 22 of the LED chip 10 are respectively bonded to the first bonding pad 41 and the second bonding pad 42 on the circuit board 40.
In step S13, the first bonding pad 41 and the second bonding pad 42 are respectively connected to the positive and negative electricity so as to short-circuit the N electrode 22 and the P electrode 21 through the communication electrode 23a, and referring to (b) in fig. 7, the N electrode 22, the P electrode 21, the first bonding pad 41 and the second bonding pad 42 are melted after heat generation by short-circuiting the connection electrode 23a, so that the first bonding pad 41 and the N electrode 22 are fused together to form the first electrode 51a, and the second bonding pad 42 and the P electrode 21 are fused together to form the second electrode 52a. Referring to fig. 7 (c), energization is continued, and the temperature at the short-circuit portion continues to rise until the communication electrode 23a reaches the melting point and fuses.
Specifically, the melting points of the first bonding pad 41 and the second bonding pad 42 are equal to the melting points of the N electrode 22 and the P electrode 21, however, in another embodiment, the melting points of the first bonding pad 41 and the second bonding pad 42 may be greater than the melting points of the N electrode 22 and the P electrode 21, so that the N electrode 22 and the P electrode 21 are melted first during die bonding; in another embodiment, the melting points of the first bonding pad 41 and the second bonding pad 42 may be smaller than those of the N electrode 22 and the P electrode 21, so that the first bonding pad 41 and the second bonding pad 42 are melted first when die bonding.
Preferably, referring to fig. 8, the die bonding method of the led chip 10 further includes step S14: and waiting for the cooling of the circuit substrate 40 and the LED chips 10, and removing the LED chips 10 which fail to be soldered on the circuit substrate 40 after cooling. The circuit substrate 40 and the LED chip 10 may be cooled in a cooling environment, or the cooling gas may be sprayed directly to the die bonding site for active cooling, or the cooling gas may be naturally cooled at normal temperature. Wherein the LED chip 10 failed in die bonding is removed from the circuit substrate 40 using the transfer head 60. The transfer head 60 is a transfer head with a suction cup or a transfer head with a certain viscosity.
Example 5:
unlike embodiment 3 and embodiment 4, in the present embodiment, the melting point of the communication electrode 23a is equal to the melting points of the first pad 41 and the second pad 42. In this embodiment, the die bonding method of the LED chip 10 includes steps S11 to S13.
In step S11, a plurality of LED chips 10 as described above are provided, and a circuit substrate 40 is provided, the first side of the circuit substrate 40 having a plurality of sets of pads, each set of pads having a first pad 41 and a second pad 42. The first pad 41 and the second pad 42 are both metal pads.
In step S12, referring to fig. 9 (a), a plurality of LED chips 10 are transferred onto the circuit board 40, and the P-electrode 21 and the N-electrode 22 of the LED chip 10 are respectively bonded to the first bonding pad 41 and the second bonding pad 42 on the circuit board 40.
In step S13, the first bonding pad 41 and the second bonding pad 42 are respectively connected to positive and negative electricity, so that the N electrode 22 and the P electrode 21 are short-circuited by the communication electrode 23a, and referring to (b) in fig. 9, the N electrode 22 and the P electrode 21 are short-circuited to generate heat, and after reaching the melting point, the N electrode 22 is fused to the second bonding pad 42 and forms the second electrode 52b with the second bonding pad 42, and the P electrode 21 is fused to the first bonding pad 41 and forms the first electrode 51b with the first bonding pad 41. Referring to fig. 9 (c), the energization is continued and the temperature at the short-circuit portion continues to rise until the communication electrode 23a reaches the melting point and melts, the first pad 41 melts, the first electrode 51b becomes the first electrode 51c, the second pad 42 melts, and the second electrode 52b becomes the second electrode 52c, at which time the short-circuited current path is naturally opened. Wherein when the communication electrode 23a reaches the melting point and fuses, the first pad 41 is at least partially melted, and the second pad 42 is at least partially melted.
Preferably, the die bonding method of the LED chip 10 further includes step S14: and waiting for the cooling of the circuit substrate 40 and the LED chips 10, and removing the LED chips 10 which fail to be soldered on the circuit substrate 40 after cooling. The circuit substrate 40 and the LED chip 10 may be cooled in a cooling environment, or the cooling gas may be sprayed directly to the die bonding site for active cooling, or the cooling gas may be naturally cooled at normal temperature. Wherein the LED chip 10 failed in die bonding is removed from the circuit substrate 40 using the transfer head 60. The transfer head 60 is a transfer head with a suction cup or a transfer head with a certain viscosity.
The foregoing description of the preferred embodiments of the present invention is not intended to limit the scope of the claims, which follow, as defined in the claims.

Claims (10)

1. An LED chip, characterized in that: the first surface of the LED chip forming electrode is respectively provided with a P electrode, an N electrode and a communication electrode, the P electrode and the N electrode are connected together by the communication electrode, and the melting point of the communication electrode is higher than that of the N electrode and the P electrode.
2. The LED chip of claim 1, wherein: the area and the width of the communication electrode are smaller than those of the P electrode and the N electrode.
3. The LED chip of claim 1, wherein: the communication electrode is rectangular shape, P electrode and N electrode set up along first direction interval, the length direction that the communication electrode was arranged along first direction is greater than the width direction that the communication electrode extended along the second direction, the width of communication electrode is less than P electrode and N electrode are in the width of second direction, first direction and second direction are perpendicular.
4. The LED chip of claim 1, wherein: the two ends of the communication electrode extend to the P electrode and the N electrode respectively and are covered by the P electrode and the N electrode.
5. A die bonding method of an LED chip is characterized in that: comprising the following steps:
step 1, providing a plurality of LED chips as defined in any one of claims 1-4, and providing a circuit substrate, wherein the circuit substrate is provided with a plurality of groups of bonding pads, and each group of bonding pads is provided with a first bonding pad and a second bonding pad;
step 2, transferring a plurality of LED chips to the circuit substrate, and enabling the P electrode and the N electrode of the LED chips to be respectively and oppositely attached to a first bonding pad and a second bonding pad on the circuit substrate;
and 3, respectively connecting the first bonding pad and the second bonding pad with positive and negative electricity so as to enable the N electrode and the P electrode to be in short circuit through the communication electrode, enabling the N electrode and the P electrode to be in short circuit and generate heat along with the short circuit, melting the N electrode to the first bonding pad and forming a first electrode with the first bonding pad after reaching a melting point, and melting the P electrode to the second bonding pad and forming a second electrode with the second bonding pad until the communication electrode reaches the melting point and fuses.
6. The die bonding method of the LED chip according to claim 5, wherein: the melting point of the communication electrode is higher than, lower than or equal to the melting points of the first bonding pad and the second bonding pad;
when the melting point of the communication electrode is higher than that of the first bonding pad and the second bonding pad, the N electrode, the P electrode, the first bonding pad and the second bonding pad are melted after being heated by short circuit of the connection electrode, so that the first bonding pad and the N electrode are fused together to form a first electrode, and the second bonding pad and the P electrode are fused together to form a second electrode;
and when the melting point of the communication electrode is equal to the melting points of the first bonding pad and the second bonding pad, in the step 3, the first bonding pad is melted and the second bonding pad is melted when the communication electrode reaches the melting point and fuses.
7. The die bonding method of the LED chip according to claim 5, wherein: the first bonding pad and the second bonding pad are respectively connected with positive and negative electricity specifically comprises the following steps: and continuously electrifying the first bonding pad and the second bonding pad for a preset time, or detecting the on-off of the communication electrode after continuously electrifying the first bonding pad and the second bonding pad, and stopping supplying power to the first bonding pad and the second bonding pad when the fusing proportion of the communication electrodes of a plurality of LED chips mounted on the circuit substrate is larger than a preset value and the electrifying time is longer than the preset time.
8. The die bonding method of the LED chip according to claim 7, wherein: detecting the on-off of the communication electrode specifically comprises: detecting the power supply current between the first bonding pad and the second bonding pad, and judging that the corresponding communication electrode is fused when the current of the power supply end is smaller than a preset value; or,
and detecting whether the LED chip is lighted or not, and judging that a communication electrode of the LED chip is fused when the LED chip is lighted.
9. The die bonding method of the LED chip according to claim 5, wherein: further comprising step 4: and waiting for the circuit substrate and the LED chips to be cooled, and removing the LED chips which are failed to be welded on the circuit substrate after the temperature is reduced.
10. The die bonding method of the LED chip according to claim 5, wherein: after the communicating electrode subsequently reaches a melting point to fuse, a portion of the communicating electrode is fused by the first electrode, and a portion of the communicating electrode is fused by the second electrode.
CN202311580704.6A 2023-11-23 2023-11-23 LED chip and LED chip die bonding method Pending CN117525259A (en)

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CN117525259A true CN117525259A (en) 2024-02-06

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