Method and apparatus for trimming microelectronic components

Abstract

The present application provides a method for trimming a microelectronic component, comprising: providing a substrate, wherein at least one microelectronic component is disposed on the substrate; heating the interface between the substrate and the microelectronic component by using a first pulsed laser beam to reduce the bonding force between the microelectronic component and the substrate; and irradiating the surface layer of the microelectronic component by using a second pulsed laser beam to generate plasma-induced shock wave at the surface layer of the microelectronic component, which makes the microelectronic component separate from the substrate. A device for trimming a microelectronic component is also provided.

Description

TECHNICAL FIELD

[0001] The present application relates to a method and apparatus for trimming microelectronic elements. BACKGROUND

[0002] With the advancement of display technology, in addition to mainstream liquid crystal displays and organic light-emitting diode displays, micro light-emitting diode displays have also been developed.

[0003] The manufacturing process of micro light-emitting diode displays generally involves growing micro light-emitting diode chips on a growth substrate, transferring the micro light-emitting diode chips to a transfer substrate, and then transferring the micro light-emitting diode chips from the transfer substrate to a display backplane. However, sometimes micro light-emitting diode chips with quality defects are transferred to the display backplane or the transfer substrate, and these defective light-emitting diode chips need to be removed.

[0004] When the display backplane is a glass carrier, the light-emitting diode chips are usually broken by laser, and the fragments are then blown away. When the display backplane is a printed circuit board, the light-emitting diode chips are usually removed by heating and desoldering, and then using a suction pen. However, this method is not very efficient, and the energy required to break the micro light-emitting diode chips using laser is large, which can easily damage the conductive lines of the display backplane. Similar problems also occur when removing other microelectronic elements that are not micro light-emitting diode chips from the substrate. SUMMARY

[0005] The present application is directed to a method and apparatus for trimming microelectronic elements, which has high efficiency and can reduce damage to the substrate.

[0006] One embodiment of the present application provides a method for trimming microelectronic elements, comprising: providing a substrate, wherein at least one microelectronic element is disposed on the substrate; heating the interface between the substrate and the microelectronic element using a first pulsed laser beam to reduce the bonding force between the microelectronic element and the substrate; and irradiating the surface layer of the microelectronic element with a second pulsed laser beam to generate a plasma-induced shock wave in the surface layer of the microelectronic element, which causes the microelectronic element to separate from the substrate.

[0007] One embodiment of the present invention provides an apparatus for trimming microelectronic components, suitable for trimming a substrate on which at least one microelectronic component is disposed. The apparatus for trimming microelectronic components includes a first laser unit and a second laser unit. The first laser unit emits a first pulsed laser beam to heat the interface between the substrate and the microelectronic component, thereby reducing the bonding force between the microelectronic component and the substrate. The second laser unit emits a second pulsed laser beam and irradiates the surface of the microelectronic component with the second pulsed laser beam to generate a plasma-induced shock wave on the surface of the microelectronic component. The shock wave causes the microelectronic component to detach from the substrate, wherein the pulse duration of the second pulsed laser beam is shorter than the pulse duration of the first pulsed laser beam.

[0008] In the method and apparatus for repairing microelectronic components according to embodiments of the present invention, since a first pulsed laser beam is used to reduce the bonding force between the microelectronic component and the substrate, and a second pulsed laser beam is used to generate shock waves to dislodge the microelectronic component, the method for repairing microelectronic components according to embodiments of the present invention is highly efficient and can shorten the working time. Furthermore, since the microelectronic component is not broken using a laser, the laser energy used in the method and apparatus for repairing microelectronic components according to embodiments of the present invention is low, thus reducing damage to the substrate. Attached Figure Description

[0009] Figures 1A-1C A cross-sectional schematic diagram illustrating the process of a method for trimming microelectronic components according to an embodiment of the present invention;

[0010] Figure 2 Show Figure 1A and Figure 1B Timing diagram of the first and second pulsed laser beams;

[0011] Figure 3 for Figure 1A A cross-sectional schematic diagram of another variation of the embodiment;

[0012] Figure 4A and Figure 4B Show each Figure 1A and Figure 1B The coverage area of ​​the first pulse laser beam and the second pulse laser beam;

[0013] Figure 5 yes Figure 1C A cross-sectional schematic diagram of another variation of the embodiment. Detailed Implementation

[0014] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same element references are used in the drawings and description to denote the same or similar parts.

[0015] Figures 1A-1C FIG. 1 shows a cross-sectional view of a flow chart of a method of trimming micro electronic elements according to an embodiment of the present application. Please refer to FIG. 1, the method of trimming micro electronic elements according to the embodiment includes the following steps. First, as shown in FIG. 1, a substrate 100 is provided, wherein the substrate 100 is configured with a plurality of micro electronic elements 200, the substrate 100 is for example a display backplane having a plurality of conductive lines 110 thereon, and the micro electronic elements 200 can be arranged in an array to form a display pixel array. In the embodiment, the micro electronic elements 200 are micro light-emitting diode chips (Micro LEDs). However, in other embodiments, the micro electronic elements 200 can also be other electronic elements, such as micro integrated circuits (Micro ICs). In the embodiment, the micro electronic elements 200 have a plurality of pads 210, and the substrate 100 is configured with the micro electronic elements 200 by welding the conductive lines 110 and the pads 210 with a plurality of bumps 70 respectively. The bumps are low-melting-point materials, such as tin. In addition, in the embodiment, the micro electronic elements 200 include a first-type semiconductor layer 220, a second-type semiconductor layer 230, and a light-emitting layer 240, wherein the light-emitting layer 240 is located between the first-type semiconductor layer 220 and the second-type semiconductor layer 230, the first-type semiconductor layer 220 is electrically connected to one of the pads 210 (for example, the pad 210 located at the lower left corner of the micro electronic element 200 in FIG. 1), and the second-type semiconductor layer 230 is electrically connected to another pad 210 (for example, the pad 210 located at the lower right corner of the micro electronic element 200 in FIG. 1). The first-type semiconductor layer 220 is for example an N-type semiconductor layer, and the second-type semiconductor layer 230 is for example a P-type semiconductor layer. However, in other embodiments, the first-type semiconductor layer 220 can also be a P-type semiconductor layer, and the second-type semiconductor layer 230 can also be an N-type semiconductor layer. In an embodiment not shown, the substrate 100 can also be a temporary transfer substrate, and the substrate 100 is configured with the micro electronic elements 200 by configuring the micro electronic elements on the substrate with a plurality of buffer portions which can be polymer materials. Figures 1A-1C Figure 1A Figure 1A Figure 1A

[0016] Figure 1A ​​​​​When the microelectronic device on the right side is to be removed due to poor quality, the interface between the substrate 100 and the microelectronic device 200 to be removed is heated by the first pulsed laser beam 50 to reduce the adhesion between the microelectronic device 200 and the substrate 100. That is, the regions of the bumps 70, the conductive lines 110 and the pads 210 at the interface are heated to achieve this. In this embodiment, heating the interface between the substrate 100 and the microelectronic device 200 by the first pulsed laser beam 50 means heating the interface between the bumps 70 and the conductive lines 110 to melt the portions of the bumps 70 at the interface.

[0017] Furthermore, as shown in Figure 1B , in the case where the portions of the bumps 70 at the interface are melted, the surface layer 202 (for example, the semiconductor epitaxial layer close to the surface) of the microelectronic device 200 to be removed is irradiated by the second pulsed laser beam 60 to generate plasma (for example, high-density plasma) at the surface layer 202 of the microelectronic device 200. The plasma collides with the bottom layer 204 of the microelectronic device 200 relative to the surface layer 202 to generate a shock wave, and as shown in Figure 1C , the shock wave will blast the microelectronic device 200 to detach the microelectronic device from the substrate 100.

[0018] Figure 2 The timing diagrams of the first and second pulsed laser beams in Figure 1A and Figure 1B are shown. Please refer to Figures 1A-1C and Figure 2In the present embodiment, the pulse duration τ2 of the second pulsed laser beam 60 is less than the pulse duration τ1 of the first pulsed laser beam 50, where the pulse duration is calculated based on the half-height width, i.e., the time duration during which the light intensity is above half of the maximum light intensity. For example, if the maximum light intensity of the pulse of the first pulsed laser beam 50 is I, then the pulse duration τ1 of the first pulsed laser beam 50 is the time duration during which the light intensity is above I / 2. In the present embodiment, the pulse duration τ2 of the second pulsed laser beam 60 falls after the second half of the pulse duration τ1 of the first pulsed laser beam 50, so that when the microelectronic device 200 is ejected by the second pulsed laser beam 60, the portions of the bumps 70 at the interface have sufficient time to be heated by the first pulsed laser beam 50 to a molten state, and the microelectronic device 200 is more easily ejected. More specifically, the pulse duration τ2 of the second pulsed laser beam 60 falls within the second half of the pulse duration τ1 of the first pulsed laser beam 50, and the starting time point T2 of the second pulsed laser beam 60 is after the midpoint T3 of the midpoint TO and the ending time point T1 of the first pulsed laser beam 50, where T3 = (TO + T1) / 2. That is, the time point T1 is the time at which the cooling of the bumps 70 begins, and the second pulsed laser beam 60 is better started at the end of the time during which the first pulsed laser beam 50 exists. In the present embodiment, the ratio of the pulse duration τ1 of the first pulsed laser beam 50 to the pulse duration τ2 of the second pulsed laser beam 60 is greater than or equal to 10 6 . Here, the order of magnitude of the pulse duration τ1 of the first pulsed laser beam 50 is μs, i.e., about 10 -6 seconds, and the order of magnitude of the pulse duration τ2 of the second pulsed laser beam 60 is ps, i.e., about 10 -12 seconds.

[0019] In the present embodiment, the wavelength of the second pulsed laser beam 60 is less than the wavelength of the first pulsed laser beam 50. In one embodiment, the ratio of the wavelength of the second pulsed laser beam 60 to the wavelength of the first pulsed laser beam 50 is greater than 0.3. For example, the wavelength of the first pulsed laser beam 50 is, for example, 1064 nanometers (nm), and the first pulsed laser beam 50 is infrared light, which is easily absorbed by the material of the bumps 70. The wavelength of the second pulsed laser beam 60 is, for example, in the range of 150 nm to 355 nm, and the second pulsed laser beam 60 is ultraviolet light, which is easily absorbed by the semiconductor layer of the microelectronic device 200, so that the second pulsed laser beam 60 is less likely to irradiate the conductive lines 110 below the microelectronic device 200 and damage the conductive lines 110.

[0020] Figures 1A-1CThe method for trimming microelectronic components can be performed using a microelectronic component trimming apparatus 20 according to this embodiment. The microelectronic component trimming apparatus 20 is suitable for trimming a substrate 100 on which at least one microelectronic component 200 is disposed. The microelectronic component trimming apparatus 20 includes a first laser unit 30 and a second laser unit 40. The first laser unit 30 emits a first pulsed laser beam 50 to heat the interface between the substrate 100 and the microelectronic component 200 to be removed, thereby reducing the bonding force between the microelectronic component 200 and the substrate 100. The second laser unit 40 emits a second pulsed laser beam 60 and irradiates the surface layer 202 of the microelectronic component 200 with the second pulsed laser beam 60, thereby generating a shock wave caused by plasma on the surface layer 202 of the microelectronic component 200. This shock wave causes the microelectronic component 200 to detach from the substrate 100. The pulse duration τ2 of the second pulsed laser beam 60 is less than the pulse duration τ1 of the first pulsed laser beam 50. Other details regarding the first pulse laser beam 50 and the second pulse laser beam 60 can be found in the documentation. Figures 1A-1C and Figure 2 The description of the embodiments will not be repeated here.

[0021] In this embodiment, the first laser unit 30 and the second laser unit 40 can be various types of laser emitters. In addition, the device 20 for trimming microelectronic components may also include a controller electrically connected to the first laser unit 30 and the second laser unit 40 to control the timing, intensity, and operation of the first laser unit 30 and the second laser unit 40.

[0022] In this embodiment, both the first pulsed laser beam 50 and the second pulsed laser beam 60 irradiate the microelectronic component 200 from the side away from the substrate 100 (i.e., from...). Figure 1A and Figure 1B (Illuminating from above to below). However, in another embodiment, the first pulsed laser beam 50 irradiates from the side of the substrate 100 away from the microelectronic component 200 (e.g., irradiating from above to below). Figure 3 As shown, by Figure 3 The second pulsed laser beam 60 irradiates from the side of the microelectronic component 200 away from the substrate 100 (i.e., from below to above), and the second pulsed laser beam 60 irradiates from the side of the microelectronic component 200 away from the substrate 100 (i.e., from below to above). Figure 1B (Irradiation from above to below) allows the interface between the substrate 100 and the microelectronic component to heat up faster, thereby reducing the bonding force between the microelectronic component 200 and the substrate 100 more quickly.

[0023] Figure 4A and Figure 4B Show each Figure 1A and Figure 1B The coverage area of ​​the first and second pulse laser beams. Please refer to... Figure 1A , Figure 1B , Figure 4A andFigure 4B In the present embodiment, the irradiation range R2 of the second pulsed laser beam 60 is smaller than the irradiation range Rl of the first pulsed laser beam 50. In addition, in the present embodiment, the irradiation range R2 of the second pulsed laser beam 60 on the top surface 201 of the micro electronic element 200 overlaps and is equal to or smaller than the area of the top surface 201 of the micro electronic element 200. In one embodiment, the spot diameter Dl of the second pulsed laser beam 60 irradiated on the micro electronic element 200 is smaller than the minimum side length D2 of the micro electronic element 200 (if the top surface 201 of the micro electronic element 200 is in the shape of a rectangle or similar, the minimum side length D2 is the short side of the rectangle). In addition, the spot diameter Dl is defined as the diameter of the range where the light intensity of the spot is 1 / e of the maximum light intensity, where e is the natural base number. The design that the irradiation range Rl of the second pulsed laser beam 60 on the top surface 201 of the micro electronic element 200 overlaps and is equal to or smaller than the area of the top surface 201 of the micro electronic element 200 can make the second pulsed laser beam 60 irradiated on the surface of the micro electronic element 200 to ensure that the laser plasma shock wave can effectively exert force on the micro electronic element 200, and can make the micro electronic element 200 block the second pulsed laser beam 60 without damaging the substrate 100 and the conductive circuit 110 thereon. 2 The above range is the diameter, where e is the natural base number. The design that the irradiation range Rl of the second pulsed laser beam 60 on the top surface 201 of the micro electronic element 200 overlaps and is equal to or smaller than the area of the top surface 201 of the micro electronic element 200 can make the second pulsed laser beam 60 irradiated on the surface of the micro electronic element 200 to ensure that the laser plasma shock wave can effectively exert force on the micro electronic element 200, and can make the micro electronic element 200 block the second pulsed laser beam 60 without damaging the substrate 100 and the conductive circuit 110 thereon.

[0024] In addition, in the present embodiment, the heating of the interface between the substrate 100 and the micro electronic element 200 by the first pulsed laser beam 50 means that the first pulsed laser beam 50 is irradiated on the interface between the substrate 100 and the micro electronic element 200 to heat the interface. However, in another embodiment, the heating of the interface between the substrate 100 and the micro electronic element 200 by the first pulsed laser beam 50 can also mean that the first pulsed laser beam 50 is irradiated on the substrate 100 or the micro electronic element 200 to generate heat energy, and the heat energy is transferred to the interface between the substrate 100 and the micro electronic element 200 through heat conduction.

[0025] In the method for trimming the micro electronic element of the present embodiment, since the first pulsed laser beam 50 is used to reduce the adhesion between the micro electronic element 200 and the substrate 100 (this step can be referred to as a thermal process), and the second pulsed laser beam 60 is used to generate a shock wave to blow off the micro electronic element 200 (this step can be referred to as a peeling process), the method for trimming the micro electronic element of the present embodiment has high efficiency and can shorten the working hours. In addition, since the micro electronic element 200 is not broken by using a laser, the laser energy used in the method for trimming the micro electronic element of the present embodiment is low, and the damage to the substrate 100 can be reduced.

[0026] Figure 5 is Figure 1C a cross-sectional view of another variant embodiment of the embodiment of Figure 1Band Figure 5 In the 1C embodiment, after the microelectronic component 200 is deflected by the second pulsed laser beam 60, the bump 70 is deflected along with the microelectronic component 200. However, in Figure 5 In one embodiment, after the second pulsed laser beam 60 dislodges the microelectronic component 200, the bump 70 is split into two parts. The upper part 74 of the bump 70 is dislodged along with the microelectronic component 200, while the lower part 72 of the bump 70 remains on the conductive line 110. That is, at least a portion of the bump 70 remains on the substrate 100 after detaching from the microelectronic component 200. The lower part 72 of the bump 70 remaining on the conductive line 110 facilitates the re-attachment of a high-quality microelectronic component 200 to the lower part 72 of the bump 70 after dislodging a defective microelectronic component 200.

[0027] In addition, Figures 1A-1C and Figure 5 In this embodiment, the parameters of the first pulsed laser beam 50 are determined as follows. The adjustable parameters are the laser peak power and the pulse length. The thermal radiation generated by the melting of the bump 70 can be used as an intermediate product, and the intensity of the thermal radiation spectrometer can be measured using a spectrometer as the optimization direction for the two-dimensional parameter scan (parameters such as power and pulse duration). Alternatively, during the two-dimensional parameter scan, high-pressure gas can be directly and synchronously applied to the target microelectronic component 200.

[0028] Furthermore, after confirming the parameters of the first pulsed laser beam 50, the parameter scanning for removing the microelectronic component 200 using the second pulsed laser beam 60 can begin. If a fixed pulse length is used, the adjustable parameter is the pulse energy (single shot). Additionally, the diameter of the laser spot should be made as small as possible, less than or equal to the minimum side length of the microelectronic component 200.

[0029] After determining the parameters of the first pulse laser beam 50 and the second pulse laser beam 60, the next parameter to be adjusted is the time difference between the two pulses.

[0030] Furthermore, the relationship between the volume of bump 70 and laser energy is (X+Y) / A. X joules are needed to raise bump 70 to the target temperature. The laser absorption rate of the material is A (subtracting reflection and transmission, this value is less than 1). The energy loss during the heating process is Y (losses due to heat conduction, convection, radiation, etc.). Therefore, the actual laser energy output to the microelectronic component 200 to be removed is (X+Y) / A. To calculate this, by determining the volume and density of bump 70, its weight can be calculated. Then, by determining its heat capacity and the expected temperature increase, the required energy absorption (denoted as X joules) can be calculated to raise bump 70 to the target temperature.

[0031] On the other hand, the relationship of the shock of the microelectronic element 200 is SxP>2 times the weight of the microelectronic element 200. Where S is the spot size of the second pulsed laser beam 60, and P is the shock wave pressure experienced by the microelectronic element 200.

[0032] In summary, in the method and apparatus for trimming microelectronic elements of the embodiments of the present application, since the first pulsed laser beam is used to reduce the bonding force between the microelectronic element and the substrate, and the second pulsed laser beam is used to generate a shock wave to shock the microelectronic element, the method for trimming microelectronic elements of the embodiments of the present application has high efficiency and can shorten the working hours. In addition, since the microelectronic element is not broken by using laser, the laser energy used by the method and apparatus for trimming microelectronic elements of the embodiments of the present application is low, and the damage to the substrate can be reduced.

[0033] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for trimming microelectronic components, characterized in that, include: A substrate is provided, wherein at least one microelectronic component is disposed on the substrate; The interface between the substrate and the microelectronic component is heated by a first pulsed laser beam to reduce the bonding force between the microelectronic component and the substrate. as well as A second pulsed laser beam is used to irradiate the surface of the microelectronic component, generating plasma-induced shock waves on the surface of the microelectronic component. These shock waves cause the microelectronic component to detach from the substrate. Wherein, the pulse period of the second pulsed laser beam is shorter than the pulse period of the first pulsed laser beam, and the pulse period of the second pulsed laser beam falls within the latter half of the pulse period of the first pulsed laser beam.

2. The method for trimming microelectronic components according to claim 1, characterized in that, The ratio of the pulse duration of the first pulsed laser beam to the pulse duration of the second pulsed laser beam is greater than or equal to 10. 6 .

3. The method for trimming microelectronic components according to claim 1, characterized in that, The start time of the second pulsed laser beam is after the midpoint between the midpoint of the pulse period of the first pulsed laser beam and the end time of the first pulsed laser beam.

4. The method for trimming microelectronic components according to claim 1, characterized in that, The ratio of the wavelength of the second pulsed laser beam to the wavelength of the first pulsed laser beam is greater than 0.

3.

5. The method for trimming microelectronic components according to claim 1, characterized in that, The irradiation range of the second pulsed laser beam is smaller than that of the first pulsed laser beam.

6. The method for trimming microelectronic components according to claim 1, characterized in that, The diameter of the spot on the microelectronic component illuminated by the second pulsed laser beam is smaller than the minimum side length of the microelectronic component.

7. The method for trimming microelectronic components according to claim 6, characterized in that, The second pulsed laser beam overlaps with the top surface of the microelectronic component in terms of its illumination range and is less than or equal to the area of ​​the top surface of the microelectronic component.

8. The method for trimming microelectronic components according to claim 1, characterized in that, The substrate has multiple conductive lines, the microelectronic component has multiple pads, and the microelectronic component is disposed on the substrate by welding the multiple conductive lines and the multiple pads together with multiple bumps.

9. The method for trimming microelectronic components according to claim 8, characterized in that, At least a portion of the bumps remain on the substrate after being detached from the microelectronic component.

10. The method for trimming microelectronic components according to claim 8, characterized in that, Heating the interface between the substrate and the microelectronic component using the first pulsed laser beam refers to heating the interface between the plurality of bumps and the plurality of conductive lines, so that the portion of the plurality of bumps located at the interface melts.

11. The method for trimming microelectronic components according to claim 1, characterized in that, Heating the interface between the substrate and the microelectronic component using the first pulsed laser beam means irradiating the substrate or the microelectronic component with the first pulsed laser beam to generate heat energy, which is then transferred to the interface between the substrate and the microelectronic component through heat conduction.

12. The method for trimming microelectronic components according to claim 1, characterized in that, Both the first pulsed laser beam and the second pulsed laser beam irradiate from the side of the microelectronic component away from the substrate.

13. The method for trimming microelectronic components according to claim 1, characterized in that, The first pulsed laser beam irradiates the substrate from the side away from the microelectronic component, and the second pulsed laser beam irradiates the microelectronic component from the side away from the substrate.

14. A device for trimming microelectronic components, characterized in that, A device suitable for trimming a substrate having at least one microelectronic component, the device comprising: A first laser unit is used to emit a first pulsed laser beam to heat the interface between the substrate and the microelectronic component, thereby reducing the bonding force between the microelectronic component and the substrate; and A second laser unit is used to emit a second pulsed laser beam and irradiate the surface of the microelectronic component with the second pulsed laser beam to generate a shock wave caused by plasma on the surface of the microelectronic component. The shock wave causes the microelectronic component to detach from the substrate, wherein the pulse period of the second pulsed laser beam is shorter than the pulse period of the first pulsed laser beam. Wherein, the pulse period of the second pulsed laser beam is shorter than the pulse period of the first pulsed laser beam, and the pulse period of the second pulsed laser beam falls within the latter half of the pulse period of the first pulsed laser beam.

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