A method of chip transfer and a transient substrate

Abstract

The present application relates to a kind of transient substrate and chip transfer method, the transient substrate is used for the transfer of chip, the transient substrate includes: substrate body, several chip bearing areas are equipped on the substrate body, one chip bearing area is used to support at least one chip;Formed on the substrate body, and the groove of the chip bearing area is communicated;Formed on each chip bearing area, adhesive layer, by the viscosity of adhesive layer, chip is fixed in the chip bearing area, and at least a part of the adhesive layer in solid state is changed into liquid state and / or vapor state when heated, and flow into the groove.In the above-mentioned groove of transient substrate, vaporized glue material can be quickly and effectively discharged, the influence of vaporized glue material on chip is prevented, the situation that chip is avoided to occur deviation, overturn, improves the quality of chip peeling.In the heating process, the glue material that is heated and melted will flow to the groove, prevents the residue of glue material, guarantees the yield of chip transfer.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more particularly to a transient substrate and chip transfer method. Background Technology

[0002] As a next-generation display technology, Micro LED offers higher brightness, better luminous efficiency, lower power consumption, and longer lifespan compared to LCD and OLED technologies. In the Micro LED manufacturing process, mass transfer of chips is a core technology, primarily encompassing selective laser transfer (SLA), pick-and-place technology, and transfer printing technology, with SLA currently being the mainstream technology.

[0003] Currently, in selective laser lift-off, the adhesive material needs to be vaporized by laser to separate the chip electrodes from the transient substrate. However, unvaporized adhesive material often remains on the chip electrode surface after laser treatment, affecting subsequent fabrication and significantly impacting the electrical properties of the chip electrodes after bonding to the backplane. Furthermore, the high-temperature vaporization of the adhesive material under laser treatment generates gas, which cannot be effectively expelled, leading to defects such as chip misalignment and flipping, severely affecting the quality of chip transfer.

[0004] Therefore, how to prevent adhesive residue during chip transfer and effectively remove vaporized adhesive is an urgent problem to be solved. Summary of the Invention

[0005] In view of the shortcomings of the above-mentioned related technologies, the purpose of this application is to provide a transient substrate and chip transfer method, which aims to solve the problems of residual adhesive material during chip transfer and the inability to effectively remove adhesive material that has vaporized due to heat.

[0006] A transient substrate for transferring a chip, the transient substrate comprising:

[0007] A substrate body, wherein a plurality of chip carrier areas are provided on the substrate body, and one chip carrier area is used to carry at least one chip;

[0008] A trench formed on the substrate body that communicates with the chip carrier area;

[0009] An adhesive layer is formed on each of the chip carrier areas, and the chip is fixed to the chip carrier area by the adhesive layer. When the adhesive layer is heated and changes from solid to liquid and / or gaseous, at least a portion of it flows into the trench.

[0010] The trenches in the aforementioned transient substrate ensure sufficient drainage space for the vaporized adhesive material after heating, allowing it to drain quickly and effectively. This prevents the vaporized adhesive from affecting the chip, avoiding chip misalignment or flipping, and improving the quality of chip peeling. Simultaneously, the melted liquid adhesive material from the heated adhesive layer flows into the trenches, preventing adhesive residue on the chip-bearing area of ​​the transient substrate surface. This further facilitates the subsequent bonding of the chip electrodes to the display backplane, ensuring a high yield rate for chip transfer.

[0011] Based on the same inventive concept, this application also provides a chip transfer method, comprising:

[0012] Provide the transient substrate as described above;

[0013] The chip is fixed to the chip carrier area by the adhesive layer;

[0014] The adhesive layer between the chip and the substrate body is selectively heated, causing the adhesive layer at the heated portion to change from a solid state to a liquid and / or a vapor state, with at least a portion of it flowing into the trench.

[0015] The chip is peeled off from the transient substrate.

[0016] In the chip transfer method described above, when the chip is peeled off from the transient substrate, the liquid and gaseous adhesive material of the adhesive layer after being heated will be effectively discharged from the trench, preventing adhesive material residue. The chip will not be affected by the gaseous adhesive material, resulting in good chip transfer quality. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a transient substrate provided in an embodiment of the present invention;

[0018] Figure 2 Provided for embodiments of the present invention Figure 1 A bottom view;

[0019] Figure 3 This is a schematic diagram of another structure of the transient substrate provided in an embodiment of the present invention;

[0020] Figure 4 Provided for embodiments of the present invention Figure 3 A bottom view;

[0021] Figure 5 The transient substrate provided in the embodiments of the present invention is Figure 3 The diagram shown illustrates a chip mounted on a transient substrate.

[0022] Figure 6 Provided for embodiments of the present invention Figure 5 A bottom view;

[0023] Figure 7 This is another structural schematic diagram of the transient substrate provided in an embodiment of the present invention;

[0024] Figure 8 Provided for embodiments of the invention Figure 7 BB section view;

[0025] Figure 9 The transient substrate provided in the embodiments of the present invention is Figure 7 The diagram shown illustrates a chip mounted on a transient substrate.

[0026] Figure 10 Provided for embodiments of the present invention Figure 9 A bottom view;

[0027] Figure 11 This is a schematic diagram of another structure of the transient substrate provided in an embodiment of the present invention;

[0028] Figure 12 Provided for embodiments of the invention Figure 11 AA section view;

[0029] Figure 13 This is another structural schematic diagram of the transient substrate provided in an embodiment of the present invention;

[0030] Figure 14 A schematic diagram of a structure in which trenches are provided on a chip carrier area according to an embodiment of the present invention;

[0031] Figure 15 Provided for embodiments of the present invention Figure 14 A bottom view;

[0032] Figure 16 The transient substrate provided in the embodiments of the present invention is Figure 14 The diagram shown illustrates a chip mounted on a transient substrate.

[0033] Figure 17 Provided for embodiments of the present invention Figure 16 A bottom view;

[0034] Figure 18 This is a schematic diagram of a structure provided in an embodiment of the present invention when a fourth trench is provided on a transient substrate;

[0035] Figure 19 This is another structural schematic diagram of a transient substrate with a fourth trench provided in an embodiment of the present invention;

[0036] Figure 20 A flowchart of a chip transfer method provided in an embodiment of the present invention;

[0037] Figure 21A schematic diagram of the chip transfer process provided in an embodiment of the present invention;

[0038] Explanation of reference numerals in the attached figures:

[0039] 1-Substrate body, 101-Chip carrier area, 102-First trench, 103-Second trench, 104-Third trench, 105-Fourth trench, 2-Chip, 3-Adhesive layer, 4-Growth substrate, 5-Transfer substrate, 6-Display backplate. Detailed Implementation

[0040] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0042] During selective laser lift-off in chip transfer, unvaporized adhesive material can easily remain on the surface of the chip electrodes, affecting subsequent fabrication and significantly impacting the electrical properties of the chip electrodes after bonding to the backplane. Furthermore, vaporized adhesive material cannot be effectively removed from the transient substrate, leading to defects such as chip misalignment and flipping, severely affecting the quality of chip transfer.

[0043] Therefore, this application aims to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in subsequent embodiments.

[0044] This embodiment provides a transient substrate for, but not limited to, chip transfer. In one example, the transient substrate can be made of any material, but not limited to, glass, ceramic, or silicon; this embodiment does not impose specific limitations on the material of the transient substrate. The shape of the transient substrate can be any shape, such as rectangular, circular, elliptical, or trapezoidal; this embodiment also does not impose specific limitations on the shape of the transient substrate.

[0045] like Figures 1-19 As shown, the transient substrate includes: substrate body 1, trench and adhesive layer 3.

[0046] The substrate body 1 is provided with a plurality of chip carrier areas 101, and one chip carrier area 101 is used to carry at least one chip 2.

[0047] In this embodiment, the shape of the chip carrier area 101 can be any one of rectangle, circle, trapezoid, triangle, or other irregular structure.

[0048] The trench is formed on the substrate body 1 and communicates with the chip carrier area 101;

[0049] An adhesive layer 3 is formed on each chip carrier area 101. The chip 2 is fixed to the chip carrier area 101 by the adhesive layer 3. When the adhesive layer 3 is heated and changes from solid to liquid and / or gaseous, at least a portion of it flows into the trench.

[0050] In this embodiment, the adhesive layer 3 is made of hot melt adhesive, such as, but not limited to, polyurethane hot melt adhesive. When the adhesive layer is heated, one possibility is that all the adhesive material is vaporized to form a gaseous state; another possibility is that all the adhesive material is melted to form a liquid state; and yet another possibility is that a portion of the adhesive material vaporizes to form a gaseous state, while a portion melts to form a liquid state.

[0051] In this embodiment, the shape of the groove is not specifically limited. For example, the groove can be any one of a rectangular groove, an arc groove, a trapezoidal groove, or a triangular groove. In this embodiment, the groove can be processed by, but is not limited to, etching processes. For example, it can also be processed by other common machining methods.

[0052] During processing, an adhesive layer 3 can be coated onto the front side of the substrate body 1 first, and then trenches can be machined on the front side; alternatively, trenches can be machined on the front side of the substrate body 1, and then an adhesive layer 3 can be coated onto the chip carrier area 101. When machining the trenches first, the adhesive material remaining in the trenches needs to be removed after coating the adhesive layer 3. This prevents the residual adhesive material in the trenches from obstructing flow and affecting the removal of adhesive material during subsequent heating and descaling. In this embodiment, an etching process can be used, but is not limited to, to remove the adhesive material.

[0053] It should be understood that chip 2 in this embodiment can be a light-emitting chip or an electronic chip. The light-emitting chip includes an epitaxial layer and electrodes. This embodiment does not limit the specific structure of the epitaxial layer of the LED chip. In one example, the epitaxial layer of the LED chip may include an N-type semiconductor, a P-type semiconductor, and an active layer located between the N-type semiconductor and the P-type semiconductor. The active layer may include a quantum well layer, and may also include other structures. In other examples, the epitaxial layer may optionally include at least one of a reflective layer and a passivation layer. The material and shape of the electrodes in this embodiment are also not limited. For example, in one example, the material of the electrodes may include, but is not limited to, at least one of Cr, Ni, Al, Ti, Au, Pt, W, Pb, Rh, Sn, Cu, and Ag.

[0054] It should be understood that LED chips may include, but are not limited to, at least one of micro-LED chips and mini-LED chips. For example, in one example, the LED chip may be a micro-LED chip; in another example, the LED chip may be a mini-LED chip.

[0055] It should be understood that the LED chip in this embodiment may include, but is not limited to, at least one of flip-chip LED chips, upright LED chips, and vertical LED chips. For example, in one example, the LED chip may be a flip-chip LED chip; in another example, the LED chip may be an upright LED chip or a vertical LED chip.

[0056] The trenches in the aforementioned transient substrate ensure sufficient drainage space for the vaporized adhesive material after heating, allowing it to drain quickly and effectively. This prevents the vaporized adhesive from affecting the chip, avoiding chip misalignment or flipping, and improving the quality of chip peeling. Simultaneously, the melted liquid adhesive material from the heated adhesive layer flows into the trenches, preventing adhesive residue on the chip-bearing area of ​​the transient substrate surface. This further facilitates the subsequent bonding of the chip electrodes to the display backplane, ensuring a high yield rate for chip transfer.

[0057] In this example, the distance from the bottom of the trench to the front side of the substrate body 1 carrying the chip 2 is 0.1 to 0.9 times the distance from the front side to the back side of the substrate body 1. The back side of the substrate body 1 is the side opposite to the front side of the substrate body 1.

[0058] For ease of understanding, this embodiment uses a rectangular chip carrier area 101. Examples of trench configuration can be found, but are not limited to, the following examples:

[0059] Example 1: such as Figures 1-4 As shown, the trench includes first trenches 102 located on both sides of the chip carrier area 101. The first trenches 102 on both sides are provided along the outer edge of the chip carrier area 101, so as to facilitate the flow of vapor and liquid adhesive materials on the chip carrier area 101 to both sides of the chip carrier area 101.

[0060] In this example, such as Figure 1 , Figure 2 As shown, the trenches between adjacent chip carrier areas 101 are the same first trench 102. That is, two adjacent chip carrier areas 101 share the same first trench 102, and the adhesive material on the two adjacent chip carrier areas 101 after being heated can flow into the same first trench 102 and eventually flow out of the transient substrate.

[0061] Or, such as Figures 3-6As shown, the trench between adjacent chip carrier areas 101 includes two first trenches 102. That is, the two adjacent chip carrier areas 101 do not share the same first trench. The adhesive material on the two adjacent chip carrier areas 101 after being heated flows into their respective adjacent first trenches 102 and eventually flows out of the transient substrate.

[0062] Example 2: such as Figures 7-13 As shown, the trench includes not only the first trench 102 in Example 1, but also the second trench 103 located on the chip carrier area.

[0063] like Figure 11 , Figure 12 As shown, in this example, the second trench 103 can be located in the middle of the chip carrier area 101 and not communicate with the first trench 102. In this case, the second trench 103 also facilitates the flow of gaseous and liquid adhesive materials from between the chip 2 electrode and the transient substrate.

[0064] like Figures 7-10 As shown, another configuration of the second trench 103 is that it is located on both sides of the chip carrier area 101 and communicates with the first trench 102. In this case, the gaseous and liquid adhesive materials can flow from between the chip 2 electrode and the transient substrate into the second trench 103, then into the first trench 102, and finally out of the transient substrate.

[0065] like Figure 13 As shown, another configuration of the second trench 103 is that it passes through the chip carrier area 101 and communicates with the first trenches 102 on both sides of the chip carrier area 101. In this case, gaseous and liquid adhesive materials can also flow into the first trench through the second trench, and the trench is in the form of a grid.

[0066] Example 3: such as Figures 14-19 As shown, the trench includes a third trench 104 located on the chip carrier region.

[0067] The third trench 104 is entirely disposed on the chip carrier area 101. The third trench 104 on the same chip carrier area 101 can be a discontinuous multiple trench structure, or it can be like... Figures 14-17 As shown, this is a continuous trench. After heating, the vapor and liquid adhesive between the chip 2 electrode and the transient substrate flows into the third trench 104, preventing adhesive residue and the influence of vapor adhesive on the chip.

[0068] Example 4: (e.g.) Figure 18 , Figure 19 As shown, the trench includes not only the third trench 104, but also a fourth trench 105 that passes through adjacent chip carrier areas 101, enabling communication between adjacent chip carrier areas 101. Both gaseous and liquid adhesives on adjacent chip carrier areas 101 can flow into the fourth trench 105.

[0069] In this example, the fourth trench 105 can communicate with the third trench 104, such as... Figure 18 As shown, it may also not be connected to the third trench 104, such as Figure 19 As shown.

[0070] Another optional embodiment of the present invention:

[0071] This embodiment provides a chip transfer method, such as... Figure 20 As shown, it includes:

[0072] S2001: Provides the transient substrate as described above;

[0073] S2002: The chip is fixed to the chip carrier area by the adhesive layer;

[0074] S2003: Selectively heating the adhesive layer between the chip and the substrate body, causing the adhesive layer at the heated part to change from a solid state to a liquid and / or vapor state, with at least a portion of it flowing into the trench.

[0075] S2004: Remove the chip from the transient substrate.

[0076] In the chip transfer method described above, when the chip is peeled off from the transient substrate, the liquid and gaseous adhesive material of the adhesive layer after being heated will be effectively discharged from the trench, preventing adhesive material residue. The chip will not be affected by the gaseous adhesive material, resulting in good chip transfer quality.

[0077] For ease of understanding, the chip transfer method described above will be explained exemplarily below in this embodiment: Figure 21 As shown,

[0078] S1: Provide the aforementioned transient substrate.

[0079] S2: The chip 2 to be transferred is aligned and bonded to the chip carrier area of ​​the transient substrate through the adhesive layer 3 on the transient substrate.

[0080] In this example, the alignment between chip 2 and the transient substrate can be achieved by marking the transient substrate first, and then attaching chip 2. This embodiment does not impose specific restrictions on the marking method, such as laser marking, but not limited to it.

[0081] S3: Peel chip 2 from growth substrate 4.

[0082] In this embodiment, the growth substrate 4 is made of a semiconductor material on which a chip epitaxial layer can be grown. For example, the material of the growth substrate 4 can be, but is not limited to, sapphire, silicon carbide, silicon, gallium arsenide, or other semiconductor materials. No limitation is made here.

[0083] S4: Attach the end of chip 2 furthest from the transient substrate to the transfer substrate 5. In this embodiment, the chip may be attached to the transfer substrate 5 using, but is not limited to, an adhesive material.

[0084] S5: Selectively heat the adhesive layer 3 between the chip 2 and the substrate body 1, causing the adhesive layer at the heated portion to change from a solid state to a liquid and / or vapor state, with at least a portion flowing into the trench. The liquid and vapor adhesive flowing into the trench can also be guided by the trench to be discharged outside the transient substrate, preventing the liquid and vapor adhesive from affecting the chip transfer.

[0085] In this example, the heating method can be, but is not limited to, laser irradiation. Selective laser removal of the adhesive material means selectively removing the adhesive material between the transient substrate and the target chip. The laser enters from the back of the transient substrate, and the non-target chip areas are not targeted. This allows for the selective peeling of the target chip from the transient substrate, transferring only the target chip while leaving the non-target chips on the transient substrate.

[0086] S6: Remove chip 2 from the transient substrate.

[0087] S7: Bond the stripped chip 2 to the display backplate 6.

[0088] In this embodiment, the bonding connection is to electrically connect the electrodes of the chip 2 to the electrodes on the display backplate 6. This bonding connection can be made using, but is not limited to, solder or anisotropic conductive adhesive.

[0089] S8: Repair the chips by adding bonded chips to the unbonded areas on the display backplate 6.

[0090] By using the above chip transfer method, vapor and liquid adhesive materials can flow into the trench during selective stripping, which can effectively discharge the vapor and liquid adhesive materials, prevent adhesive material residue, and prevent the chip from being affected by vaporized adhesive materials, thereby improving the chip transfer yield.

[0091] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A transient substrate, said transient substrate being used for chip transfer, characterized in that, The transient substrate includes: A substrate body, wherein a plurality of chip carrier areas are provided on the substrate body, and one chip carrier area is used to carry at least one chip; A trench formed on the substrate body and communicating with the chip carrier area; the trench includes sub-trenches located on the chip carrier area; An adhesive layer is formed on each of the chip carrier areas, and the chip is fixed to the chip carrier area by the adhesive layer. When the adhesive layer is heated and changes from solid to liquid and / or gaseous, at least a portion of it flows into the trench.

2. The transient substrate as described in claim 1, characterized in that, The sub-groove is a second trench, and the second trench is located in the middle of the chip carrier area; or, The second trench is located at the edges of both sides of the chip carrier area; or, The second trench passes through the adjacent chip carrier area.

3. The transient substrate as described in claim 1 or 2, characterized in that, The trench also includes a first trench located on both sides of the chip carrier area.

4. The transient substrate as described in claim 3, characterized in that, The trenches between adjacent chip carrier areas are the same first trench; Alternatively, the trench between adjacent chip carrier areas may include two of the first trenches.

5. The transient substrate as described in claim 1, characterized in that, The sub-trench is a third trench, and the third trench extends toward the extending direction of the chip carrier area; The third trench penetrates the chip carrier area; or, the third trench includes a plurality of groove structures arranged and spaced apart along the extension direction of the chip carrier area.

6. The transient substrate as described in claim 5, characterized in that, The trench also includes a fourth trench that passes through the adjacent chip carrier area, so that the adjacent chip carrier areas are connected.

7. The transient substrate as described in claim 6, characterized in that, The fourth groove is located between the third grooves and may or may not be connected to the third grooves.

8. A chip transfer method, characterized in that, include: Provide a transient substrate as described in any one of claims 1-7; The chip is fixed to the chip carrier area by the adhesive layer; The adhesive layer between the chip and the substrate body is selectively heated, causing the adhesive layer at the heated portion to change from a solid state to a liquid and / or a vapor state, with at least a portion of it flowing into the trench. The chip is peeled off from the transient substrate.

9. The chip transfer method as described in claim 8, characterized in that, After fixing the chip to the chip carrier area; before selectively heating the adhesive layer between the chip and the substrate body, the method further includes: The chip is peeled off from the growth substrate; The end of the chip furthest from the transient substrate is attached to the transfer substrate.

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