Method for dipping of adhesive material

Abstract

The present invention relates to a method for dipping an adhesive material. A method for dipping an adhesive material according to one aspect of the present invention is characterized by comprising the steps of: dipping an adhesive material into a first dipping stamp; transferring the adhesive material dipped into the first dipping stamp onto a target substrate; and transferring a device onto the target substrate on which the adhesive material has been transferred.

Description

Technology Field

[0001] The present invention relates to an adhesive material dipping method that enables the selective application of an adhesive material onto a target substrate. Background Technology

[0003] Recently, due to the difficulties in miniaturizing semiconductor devices under Moore's Law, limitations are emerging in the improvement of integration density at the semiconductor front-end process level.

[0004] Accordingly, semiconductor companies and research institutes are focusing on the miniaturization of solder bump pitch during the packaging stage. Furthermore, for Micro LED displays, which are currently considered the next-generation technology in the display market, development of transfer / bonding and repair processes is underway to highly integrate LED chips ranging in size from 50 μm to 10 μm to hundreds to thousands of ppi. Consequently, there is a rapidly increasing demand for the selective application of adhesive materials for bonding between devices and solders at resolutions of tens of μm or less.

[0005] Conventional methods for applying adhesive materials can be classified according to the type of material. For film-type materials, methods include lamination using thermal compression or vacuum, while for paste-type materials, methods include dispensing, screen printing, spin coating, bar coating, and ink-jet printing. Among these, lamination, spin coating, and bar coating are batch coating methods, making it impossible to selectively apply the material to specific areas. Screen printing and dispensing allow for selective material application, but since the applicable resolution is 100 μm or higher, they cannot be utilized for device bonding with a resolution of tens of μm or less. Ink-jet printing is suitable for applying adhesive materials at resolutions of tens of μm or less, but its very slow process speed limits its application in mass production.

[0006] The background technology of the present invention is disclosed in Korean Published Patent Application No. 10-2017-0058341 (published May 26, 2017). The problem to be solved

[0008] According to one aspect, the technical problem to be solved by the present invention is to provide an adhesive material dipping method that enables the selective application of an adhesive material to a specific area within tens of μm on a target substrate. means of solving the problem

[0010] According to one aspect of the present invention, the present invention provides an adhesive material dipping method comprising the steps of: dipping an adhesive material into a first dipping stamp; transferring the adhesive material dipped into the first dipping stamp to a target substrate; and transferring a device onto the target substrate on which the adhesive material has been transferred.

[0011] In the present invention, the first dipping stamp comprises a base portion and an uneven portion provided on the base portion, and the uneven portion may include at least one protrusion.

[0012] In the present invention, the adhesive material may be in the form of a film or paste and may be composed of at least one of a curable resin, a reducing agent, a thermoplastic resin, a curing agent, and a solder.

[0013] In the present invention, the dipping step may include the step of applying pressure after contacting the first dipping stamp onto the adhesive material while the adhesive material is heated, the step of separating the first dipping stamp from the adhesive material after cooling the adhesive material, and the step of dipping the adhesive material into the protrusion of the first dipping stamp.

[0014] In the present invention, the shape and volume of the adhesive material dipped in the first dipping stamp can be determined based on at least one of the protrusion of the first dipping stamp and the surface condition of the adhesive material, the heating temperature, and the applied pressure.

[0015] The present invention may further include a step of forming the adhesive material into a flat film or paste by heating or blading the separated adhesive material after the step of dipping the adhesive material into the protrusion of the first dipping stamp.

[0016] In the present invention, the target substrate may include a substrate base portion and at least one device junction portion disposed on the upper surface of the substrate base portion.

[0017] In the present invention, the step of transferring the dipped adhesive material to a target substrate may include the step of contacting each of the protrusions on which the adhesive material of the first dipping stamp is dipped with the corresponding device junction of the target substrate while the target substrate is heated, the step of separating the first dipping stamp from the target substrate after cooling the dipped adhesive material and the target substrate, and the step of transferring the dipped adhesive material to the device junction.

[0018] The present invention may further include a step of performing a surface treatment process on the target substrate prior to the step of contacting each of the protrusions dipped with the adhesive material of the first dipping stamp with the corresponding device junction of the target substrate.

[0019] In the present invention, the step of transferring a device onto the target substrate may include the step of transferring the device to a device junction portion of the target substrate dipped with the adhesive material using a transfer process, and the step of electrically connecting the device to a substrate base portion of the target substrate by activating the dipped adhesive material to electrically and physically connect the device to the device junction portion.

[0021] Additionally, according to another aspect of the present invention, the present invention provides an adhesive material dipping method comprising the steps of: dipping an adhesive material into a second dipping stamp having at least one element; and transferring and bonding the at least one element onto a target substrate through the adhesive material dipped into the second dipping stamp.

[0022] In the present invention, the second dipping stamp comprises an interposer and at least one element provided in the interposer, and the interposer may be a substrate in which an adhesive layer is formed in the form of a film or a pattern array on at least one of Si, glass, quartz, and a polymer film.

[0023] In the present invention, the adhesive material may be in the form of a film or paste and may be composed of at least one of a curable resin, a reducing agent, a thermoplastic resin, a curing agent, and a solder.

[0024] In the present invention, the dipping step may include the step of applying pressure after contacting the second dipping stamp onto the adhesive material while the adhesive material is heated, the step of separating the second dipping stamp from the adhesive material after cooling the adhesive material, and the step of dipping the adhesive material into the element of the second dipping stamp.

[0025] In the present invention, the shape and volume of the adhesive material dipped in the second dipping stamp can be determined based on at least one of the element of the second dipping stamp, the surface condition of the adhesive material, the heating temperature, and the applied pressure.

[0026] The present invention may further include a step of forming the adhesive material into a flat film or paste by heating or blading the separated adhesive material after the step of dipping the adhesive material into the element of the second dipping stamp.

[0027] In the present invention, the target substrate may include a substrate base portion and at least one device junction portion disposed on the upper surface of the substrate base portion.

[0028] In the present invention, the step of transferring and bonding at least one element onto a target substrate may include: contacting each element dipped with the adhesive material of the second dipping stamp with a corresponding element bonding portion of the target substrate, activating the dipped adhesive material to form an electrical and physical connection between the element and the element bonding portion, and separating the interposer of the second dipping stamp from the element, thereby transferring and bonding the element onto the target substrate.

[0029] In the present invention, the step of forming an electrical and physical connection between the device and the device junction is to move a second dipping stamp toward the target substrate so that each device dipped in the adhesive material is placed on the device junction of the corresponding target substrate and make contact, and to apply an external force to activate the dipped adhesive material, and to electrically and physically connect the device and the device junction by the activated adhesive material.

[0030] The present invention may further include a step of performing a surface treatment process on the target substrate prior to the step of contacting each of the dipped elements of the second dipping stamp with the element bonding portion of the corresponding target substrate. Effects of the invention

[0032] According to one aspect of the present invention, the present invention has the effect of improving the yield and speed of transfer, bonding, and repair processes for semiconductor devices including MLCCs, CMOS chips, ASICs, HBMs, SoCs, etc., and display devices including Micro LEDs, Mini LEDs, etc., by performing selective coating of an adhesive material through dipping of an adhesive material using a stamp at a high resolution of tens of μm and within a few seconds.

[0033] In addition, according to one aspect of the present invention, by presenting a new process that enables selective coating of an adhesive material at a high resolution of tens of μm at a high process speed, the present invention can contribute to the high integration and productivity improvement of displays, wearable devices, artificial intelligence semiconductors, system semiconductors, quantum computing devices, optical communication modules, etc.

[0034] Furthermore, according to one aspect of the present invention, by forming protrusions (or elements) within a dipping stamp in accordance with the arrangement of an element array to be bonded on a target substrate and selectively applying an adhesive material only at desired locations on the target substrate with a resolution of tens of μm, only the elements to be bonded can be transferred and bonded onto the target substrate regardless of the arrangement of elements placed on a transfer substrate or a parent substrate. Moreover, this enables the simplification of the interposer fabrication process during micro LED display production and the high integration of chiplet-based heterojunctions during semiconductor packaging.

[0035] Furthermore, according to one aspect of the present invention, when repair is required for a defective device, the invention involves fabricating a dipping stamp capable of applying an adhesive material at the single-device level and utilizing it multiple times to selectively apply the adhesive material only to the areas requiring repair on a target substrate. This eliminates the need to fabricate a new repair interposer tailored to the arrangement of defective devices to be repaired every time a repair is required. Through this, the complex processes of conventional device repair technology are simplified and process time is significantly reduced, thereby greatly improving the productivity of micro LED display fabrication and chiplet heterojunctions. Brief explanation of the drawing

[0037] FIG. 1 is a cross-sectional view illustrating a dipping stamp according to one embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a method for dipping an adhesive material using a first dipping stamp according to an embodiment of the present invention. Figure 3 is a diagram showing the experimental results of actually carrying out the process illustrated in Figure 2. FIG. 4 is a cross-sectional view illustrating an interposer-based dipping stamp according to another embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating a method for dipping an adhesive material using a second dipping stamp according to an embodiment of the present invention. Figure 6 is a graph showing experimental results regarding the change in viscosity according to heating time of an underfill film, which is one of the adhesive materials according to one embodiment of the present invention. FIG. 7 is a drawing for explaining a tiling process according to another embodiment of the present invention. FIG. 8 is a drawing for explaining a tiling process according to another embodiment of the present invention. FIG. 9 is a flowchart illustrating a method for dipping an adhesive material using a first dipping stamp according to an embodiment of the present invention. FIG. 10 is a flowchart illustrating a method for dipping an adhesive material using a second dipping stamp according to an embodiment of the present invention. Specific details for implementing the invention

[0038] Hereinafter, an example of an adhesive material dipping method according to one embodiment of the present invention is described.

[0039] In this process, the thickness of lines or the size of components depicted in the drawings may be exaggerated for the sake of clarity and convenience of explanation. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intent or convention of the user or operator. Therefore, the definitions of these terms should be based on the content throughout this specification.

[0040] Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0041] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0042] The implementations described herein may be implemented, for example, as methods or processes, devices, software programs, data streams, or signals. Even if discussed only in the context of a single form of implementation (e.g., discussed only as a method), the implementation of the discussed features may also be implemented in other forms (e.g., devices or programs). Devices may be implemented in appropriate hardware, software, and firmware, etc. Methods may be implemented in devices such as processors, which generally refer to processing devices including, for example, computers, microprocessors, integrated circuits, or programmable logic devices.

[0044] The present invention relates to a process for selectively applying an adhesive material to a specific area within tens of μm on a desired substrate by dipping the adhesive material using a stamp.

[0045] The present invention relates to an adhesive material dipping method that enables the transfer / bonding and repair of semiconductor devices and display devices onto a target substrate at a fast process speed within seconds at a resolution of tens of μm.

[0046] FIG. 1 is a cross-sectional view illustrating a dipping stamp according to one embodiment of the present invention.

[0047] Referring to FIG. 1, a dipping stamp (100) according to one embodiment of the present invention may include a base portion (101) and an uneven portion (102).

[0048] The base portion (101) may be Si, Glass, Quartz, or a polymer film, but is not limited thereto.

[0049] The uneven surface (102) may be provided on the lower surface of the base portion (101). However, if the dipping stamp (100) is flipped upside down, the uneven surface (102) may be provided on the upper surface of the base portion (101). Depending on how the dipping stamp (100) is positioned, the relative positional relationship between the base portion (101) and the uneven surface (102) may vary.

[0050] The uneven surface (102) may include at least one protrusion (103). Multiple protrusions (103) may be spaced apart from each other. The empty space between two adjacent protrusions (103) may be considered a type of "depression." Therefore, the uneven surface (102) can be seen as having a structure in which protrusions (103) and depressions are alternately arranged.

[0051] The protrusion (103) may have a width or diameter of several hundred μm or less.

[0052] The protrusion (103) can be formed from one of the following materials: a photosensitive liquid, a photosensitive organic material, a metal, a ceramic, or a polymer compound.

[0053] One or more protrusions (103) may exist on the base part (101).

[0054] The base portion (101) and the uneven portion (102) may be composed of different materials as shown in (a) of FIG. 1, but may also be composed of the same material as shown in (b) of FIG. 1.

[0055] In the case where the base portion (101) and the uneven portion (102) are composed of the same material, the dipping stamp (100) may be formed by dry / wet etching a part of the base portion (101) into one or more protrusions (103) so that both the base portion (101) and the protrusions (103) are made of the same material. At this time, the base portion (101) may be Si, Glass, Quartz, or a polymer film, but is not limited thereto.

[0056] The dipping stamp (100) configured as described above has a protrusion (103) formed to match the arrangement of the element array to be bonded on the target substrate (400), and allows the adhesive material (200) to be selectively applied only to desired locations on the target substrate (400) with a resolution of several tens of μm. That is, the dipping stamp (100) is manufactured to match the shape and location of the element to be bonded on the target substrate (400), and the bonding material can be selectively applied in a single bonding material dipping and transfer process using the dipping stamp (100).

[0057] For convenience of explanation, the dipping stamp (100) shown in FIG. 1 will be referred to as the first dipping stamp below.

[0059] FIG. 2 is a cross-sectional view illustrating a method for dipping an adhesive material using a first dipping stamp according to an embodiment of the present invention.

[0060] First, as illustrated in FIG. 2(a), the adhesive material (200) can be heated to a certain temperature (T), and the first dipping stamp (100) can be moved close to the adhesive material (200). That is, the adhesive material (200) can be heated to a certain temperature (T) to lower the viscosity of the adhesive material (200) so that the adhesive material (200) can be dipped into the first dipping stamp (100), and the dipping stamp (100) can be moved close to the adhesive material (200). Here, the adhesive material (200) may be in the form of a film or paste and may be composed of one or more of a curable resin, a reducing agent, a thermoplastic resin, a curing agent, and a solder.

[0061] The adhesive material (200) can be heated using various heating processes such as a halogen lamp, infrared heating, resistance heating, arc heating, induction heating, dielectric heating, and electron beam heating. As an example, infrared heating may include a process of irradiating an infrared (IR) laser. At this time, the adhesive material (200) may be heated to, for example, 80°C to 100°C.

[0062] Next, as shown in FIG. 2(b), the first dipping stamp (100) can be brought into contact with the adhesive material (200), and then the first dipping stamp (100) can be pressed with a constant pressure (P). At this time, the adhesive material (200) may be in a heated state.

[0063] Next, as shown in (c) of FIG. 2, the adhesive material (200) can be cooled to room temperature, and then the first dipping stamp (100) can be separated from the adhesive material (200). At this time, the adhesive material (200) can be cooled using various cooling sources such as nitrogen, cooling water, or liquid.

[0064] When the adhesive material (200) is cooled and the first dipping stamp (100) is separated, the adhesive material (300) can be dipped into the protrusion (103) of the dipping stamp (100). At this time, the shape and volume (V) of the adhesive material (300) dipped onto the first dipping stamp (100) can be determined by at least one of the surface condition, temperature (T), and pressure (P) of the protrusion (103) and the adhesive material (200) within the first dipping stamp (100). That is, the amount, shape, etc. of the adhesive material (300) dipped into the protrusion (103) may differ based on at least one of the surface condition, temperature (T), and pressure (P) of the protrusion (103) and the adhesive material (200) within the dipping stamp (100).

[0065] After the dipping of the adhesive material (200) is completed, the viscosity of the adhesive material (200) is lowered by heating to remove the dipped marks within the adhesive material (200), thereby allowing the adhesive material (200) to be formed into a flat film or paste identical to the state before dipping. Additionally, the adhesive material (200) can be formed into a flat film or paste by blading the separated adhesive material (200). Thus, the adhesive material (200) can be formed into a flat film or paste by heating or blading the separated adhesive material (200).

[0066] Next, as shown in (d) of FIG. 2, after aligning the first dipping stamp (100) containing the dipped adhesive material (300) with the target substrate (400) while the target substrate (400) is heated, the first dipping stamp (100) can be moved closer to the target substrate (400).

[0067] That is, while the target substrate (400) is heated by a heating process, the first dipping stamp (100) can be moved toward the target substrate (400) so that each of the protrusions (103) on which the adhesive material (300) is dipped is placed on the corresponding device junction (401) of the target substrate (400). At this time, the target substrate (400) can be heated using various heating processes such as a halogen lamp, infrared heating, resistance heating, arc heating, induction heating, dielectric heating, and electron beam heating. As an example, infrared heating may include a process of irradiating an infrared (IR) laser. At this time, the target substrate (400) can be heated to, for example, 80°C to 100°C.

[0068] The target substrate (400) may include a device junction (401) and a substrate base (402).

[0069] The device junction (401) may be a thin film metal composed of one or more of chromium (Cr), titanium (Ti), molybdenum (Mo), aluminum (Al), gold (Au), copper (Cu), and nickel (Ni), or may include a solder composed of an alloy selected from metals or non-metals such as tin (Sn), silver (Ag), copper (Cu), lead (Pb), bismuth (Bi), indium (In), cadmium (Cd), antimony (Sb), gallium (Ga), arsenic (As), germanium (Ge), zinc (Zn), aluminum (Al), gold (Au), silicon (Si), nickel (Ni), and phosphorus (P), and combinations thereof.

[0070] The substrate base portion (402) may be one of a backplane, a PCB, or an integrated circuit, but is not limited thereto. For example, if the substrate base portion (402) is composed of a backplane, the backplane may be one of an Oxide TFT backplane, a CMOS backplane, an LTPS Si backplane, or an a-Si backplane, but is not limited thereto.

[0071] In order to facilitate the application of the dipped adhesive material (300) onto the target substrate (400), a surface treatment process including oxygen plasma and ultraviolet treatment may be performed on the target substrate (400) before performing (d) of FIG. 2. When a surface treatment process is performed on the target substrate (400), the adhesive material (300) can be applied more effectively onto the target substrate (400).

[0072] Next, as shown in (e) of FIG. 2, the first dipping stamp (100) can be brought into contact with the target substrate (400). At this time, the target substrate (400) may be in a heated state. Therefore, when the dipping stamp (100) is brought into contact (attached) with the target substrate (400) in a heated state, the adhesive material (300) dipped in the dipping stamp (100) can be dipped (coated) as it flows down onto the target substrate (400).

[0073] Next, after cooling the dipped adhesive material (300) and the target substrate (400) to room temperature, the first dipping stamp (100) is separated from the target substrate (400) as shown in (f) of FIG. 2, so that the dipped adhesive material (300) can be transferred (dipped, applied) to the device junction (401). At this time, the adhesive material (300) and the target substrate (400) can be cooled using various cooling sources such as nitrogen, cooling water, or liquid.

[0074] Next, as illustrated in (g) of FIG. 2, a device (500) can be transferred onto a target substrate (400) on which an adhesive material (300) is dipped using various transfer processes. For example, a device (500) can be transferred onto a target substrate (400) using transfer processes such as laser-induced forward transfer, electrostatic transfer, fluidic-based assembly transfer, elastomer stamp transfer, roll-to-roll / R2R transfer, vacuum suction-based transfer, and electromagnetic transfer. Here, the device (500) may be one of an MLCC, a CMOS chip, an ASIC, an HBM, an SoC, a micro LED, or a mini LED, but is not limited thereto.

[0075] When one or more of the external forces of heat, laser, and pressure are applied, the adhesive material (300) dipped into the target substrate (400) is activated, and the device (500) transferred onto the target substrate (400) can form an electrical and physical connection with the device junction (401) by means of the activated adhesive material (300). Then, the device (500) can be electrically connected to the substrate base (402) of the target substrate (400).

[0077] Figure 3 is a diagram showing the experimental results of actually carrying out the process illustrated in Figure 2.

[0078] FIG. 3(a) is an enlarged bottom view of a first dipping stamp (100) made using a Si substrate and a photosensitive organic material. This shows a first dipping stamp (100) in which protrusions (103) for applying adhesive material are formed by patterning the photosensitive organic material coated on the Si substrate through a photolithography process.

[0079] FIG. 3(b) is a bottom view illustrating an adhesive material (300) dipped onto a first dipping stamp (100) produced in FIG. 3(a). Referring to FIG. 3(b), it can be seen that the adhesive material (300) is dipped onto a protrusion (103) of the dipping stamp (100).

[0080] FIG. 3(c) is an enlarged bottom view of a target substrate (400) including a device junction (401), and FIG. 3(d) is a bottom view for explaining an adhesive material (300) applied only on the device junction (401) of the target substrate (400) of FIG. 3(c). After preparing a target substrate (400) including a device junction (401) as shown in FIG. 3(c), if the dipping stamp (100) of FIG. 3(b) is brought into contact with the target substrate (400), as shown in FIG. 3(d), it can be confirmed that the adhesive material (300) dipped in the dipping stamp (100) is selectively applied only to the device junction (401) of the target substrate (400).

[0082] FIG. 4 is a cross-sectional view illustrating an interposer-based dipping stamp according to another embodiment of the present invention.

[0083] Referring to FIG. 4, an interposer-based dipping stamp (600) according to another embodiment of the present invention may include an interposer (601) and at least one element (500).

[0084] The interposer (601) may be a type of transfer substrate that rearranges the elements (500) formed on the mother substrate into an array of elements (500) designed on the actual target substrate (400).

[0085] The interposer (601) may be a substrate on which an adhesive layer is formed in the form of a film or a pattern array having a width of within several hundred μm on a Si, Glass, Quartz, or polymer film.

[0086] The adhesive layer constituting the interposer (601) may be PDMS or a UV-curing film, but is not limited thereto.

[0087] The element (500) may be provided on the lower surface of the interposer (601). However, if the interposer-based dipping stamp (600) is flipped upside down, the element (500) may be provided on the upper surface of the interposer (601). Depending on how the interposer-based dipping stamp (600) is positioned, the relative positional relationship between the interposer (601) and the element (500) may vary.

[0088] Multiple elements (500) can be spaced apart from each other.

[0089] The device (500) may be one of an MLCC, a CMOS chip, an ASIC, an HBM, a SoC, a micro LED, or a mini LED, but is not limited thereto.

[0090] For convenience of explanation, the interposer-based dipping stamp (600) shown in FIG. 4 will be referred to as the second dipping stamp below.

[0092] FIG. 5 is a cross-sectional view illustrating a method for dipping an adhesive material using a second dipping stamp according to an embodiment of the present invention.

[0093] First, as illustrated in FIG. 5(a), the adhesive material (200) can be heated to a certain temperature (T), and the second dipping stamp (600) can be moved close to the adhesive material (200). That is, the adhesive material (200) can be heated to a temperature (T) to lower the viscosity so that the adhesive material (200) can be dipped into the second dipping stamp (600), and the second dipping stamp (600) can be moved close to the adhesive material (200). Here, the adhesive material (200) may be in the form of a film or paste and may consist of one or more of a curable resin, a reducing agent, a thermoplastic resin, a curing agent, and a solder.

[0094] The adhesive material (200) can be heated using various heating processes such as a halogen lamp, infrared heating, resistance heating, arc heating, induction heating, dielectric heating, and electron beam heating. As an example, infrared heating may include a process of irradiating an infrared (IR) laser. At this time, the adhesive material (200) may be heated to, for example, 80°C to 100°C.

[0095] Next, as shown in FIG. 5(b), the second dipping stamp (600) can be brought into contact with the adhesive material (200), and then the second dipping stamp (600) can be pressed with a constant pressure (P). At this time, the adhesive material (200) may be in a heated state.

[0096] Next, as shown in FIG. 5 (c), the adhesive material (200) can be cooled to room temperature, and then the second dipping stamp (600) can be separated from the adhesive material (200). At this time, the adhesive material (200) can be cooled using various cooling sources such as nitrogen, cooling water, or liquid.

[0097] When the adhesive material (200) is cooled and the second dipping stamp (600) is separated, the adhesive material (300) can be dipped into the element (500) of the second dipping stamp (600). At this time, the shape and volume (V) of the adhesive material (300) dipped into the second dipping stamp (600) can be determined by at least one of the surface condition, temperature (T), and pressure (P) of the element (500) and the adhesive material (200) within the second dipping stamp (600). That is, the amount, shape, etc. of the adhesive material (300) dipped into the element (500) may differ based on at least one of the surface condition, temperature (T), and pressure (P) of the element (500) and the adhesive material (200) within the second dipping stamp (600).

[0098] After the dipping of the adhesive material (200) is completed, the viscosity of the adhesive material (200) is lowered by heating to remove the dipping marks within the adhesive material (200), thereby allowing the adhesive material (200) to be formed into a flat film or paste identical to the state before dipping. Additionally, the adhesive material (200) can be formed into a flat film or paste by blading the separated adhesive material (200). Thus, the adhesive material (200) can be formed into a flat film or paste by heating or blading the separated adhesive material (200).

[0099] Next, as shown in FIG. 5 (d), with the target substrate (400) heated, a second dipping stamp (600) containing the dipped adhesive material (300) can be aligned on the target substrate (400), and then the second dipping stamp (600) can be moved closer to the target substrate (400).

[0100] That is, while the target substrate (400) is heated by a heating process, the second dipping stamp (600) can be moved toward the target substrate (400) so that each device (500) dipped with the adhesive material (300) is placed on the device junction (401) of the corresponding target substrate (400). At this time, the target substrate (400) can be heated using various heating processes such as a halogen lamp, infrared heating, resistance heating, arc heating, induction heating, dielectric heating, and electron beam heating. As an example, infrared heating may include a process of irradiating an infrared (IR) laser. At this time, the target substrate (400) can be heated to, for example, 80°C to 100°C.

[0101] The target substrate (400) may include a device junction (401) and a substrate base (402).

[0102] The device junction (401) may include a thin film metal composed of one or more of chromium (Cr), titanium (Ti), molybdenum (Mo), aluminum (Al), gold (Au), copper (Cu), and nickel (Ni), or a solder composed of an alloy selected from metals or non-metals such as tin (Sn), silver (Ag), copper (Cu), lead (Pb), bismuth (Bi), indium (In), cadmium (Cd), antimony (Sb), gallium (Ga), arsenic (As), germanium (Ge), zinc (Zn), aluminum (Al), gold (Au), silicon (Si), nickel (Ni), and phosphorus (P), and combinations thereof.

[0103] The substrate base portion (402) may be one of a backplane, a PCB, or an integrated circuit, but is not limited thereto. For example, if the substrate base portion (402) is composed of a backplane, the backplane may be one of an Oxide TFT backplane, a CMOS backplane, an LTPS Si backplane, or an a-Si backplane, but is not limited thereto.

[0104] To facilitate the transfer of the dipped adhesive material (300) onto the target substrate (400), a surface treatment process including oxygen plasma and ultraviolet treatment may be performed on the target substrate (400) before carrying out the process illustrated in (d) of FIG. 5. When a surface treatment process is performed on the target substrate (400), the adhesive material (300) can be better applied (transferred) onto the target substrate (400).

[0105] Next, as illustrated in FIG. 5(e), after contacting the second dipping stamp (600) onto the target substrate (400), the adhesive material (300) can be activated to form an electrical and physical connection between the device (500) and the device junction (401). That is, after contacting (attaching) the second dipping stamp (600) onto the target substrate (400), one or more external forces such as heat, laser, and pressure can be applied to activate the adhesive material (300) dipped onto the target substrate (400). Then, an electrical and physical connection can be formed between the device (500) and the device junction (401) by the activated adhesive material (300).

[0106] Next, as shown in (f) of FIG. 5, the dipped adhesive material (300) is cooled to room temperature, and then the interposer (601) is separated from the device (500) so that the device (500) can finally be transferred (coated, dipped) and bonded onto the target substrate (400). At this time, the adhesive material (300) can be cooled using various cooling sources such as nitrogen, cooling water, or liquid.

[0107] Meanwhile, in an embodiment of the present invention, as shown in FIG. 5 (d), the second dipping stamp (600) is moved toward the target substrate (400) so that each of the elements (500) dipped with the adhesive material (300) is placed on the element junction (401) of the corresponding target substrate (400) while the target substrate (400) is heated. However, in FIG. 5 (e), when heat is applied to the target substrate (400) to activate the adhesive material (300) or when a laser is irradiated on the adhesive material (300) and its surroundings, the second dipping stamp (600) may be moved toward the target substrate (400) without heating the target substrate (400) as in FIG. 5 (d) so that each of the elements (500) dipped with the adhesive material (300) is placed on the element junction (401) of the corresponding target substrate (400).

[0109] Meanwhile, among the adhesive materials (200) in the form of a film or paste, the viscosity at room temperature 25℃ is 10 5 It is Pa·s or higher, and the viscosity is 10 at high temperatures of 80℃ or higher. 4 If the composition is Pa·s or less, it can be used as an adhesive material (200) according to an embodiment of the present invention.

[0110] Figure 6 is a graph showing experimental results regarding the change in viscosity according to heating time of an underfill film, which is one of the adhesive materials according to one embodiment of the present invention.

[0111] Referring to FIG. 6, it can be seen that the adhesive material (200) drops more than 10 times in viscosity instantly from the start of heating and shows the lowest viscosity, and then gradually increases in viscosity over time.

[0112] Therefore, in order to reproducibly control the viscosity of the adhesive material (300) in the process according to the embodiment of the present invention, rapid heating and cooling of the adhesive material (200) is essential.

[0113] Accordingly, in the process according to the embodiment of the present invention, one of a halogen lamp or an infrared laser may be used as a heat source to rapidly raise the temperature of the adhesive material (200), but is not limited thereto. In addition, nitrogen or a cooling water stream may be used as a cooling source to rapidly cool the adhesive material (200), but is not limited thereto.

[0114] If the adhesive material (200) is not cured or is barely cured by rapid heating using either a halogen lamp or an infrared laser, the dipped adhesive material (300) applied on the target substrate (400) according to an embodiment of the present invention can be used in a tiling process. In this case, being barely cured may mean, for example, a degree of curing of 0.2 or less.

[0116] FIG. 7 is a drawing for explaining a tiling process according to another embodiment of the present invention.

[0117] First, as shown in FIG. 7 (a), a dipped adhesive material (300) can be applied on a target substrate (400) including a device junction (401) and a substrate base (402). At this time, the dipped adhesive material (300) can be applied on the target substrate (400) using the adhesive material application method shown in FIG. 2 and FIG. 4.

[0118] Next, as illustrated in FIG. 7(b), the device (500) can be transferred onto some of the device junctions (401) using various transfer processes. For example, the device (500) can be transferred using transfer processes such as laser-induced forward transfer, electrostatic transfer, fluidic-based assembly transfer, elastomer stamp transfer, roll-to-roll / R2R transfer, vacuum suction-based transfer, and electromagnetic transfer.

[0119] One or more external forces, such as heat, laser, and pressure, may be applied to the device (500) transferred onto the device junction (401) through various transfer processes. The dipped adhesive material (300) is activated by these external forces, and an electrical and physical connection may be formed between the device (500) and the device junction (401) by the activated adhesive material (300).

[0120] Next, the device (500) can be transferred and bonded onto the target substrate (400) by repeating the transfer and bonding of the device (500) onto the device junction (401) where the device (500) has not been transferred, as shown in (c), (d), and (e) of FIG. 7.

[0122] FIG. 8 is a drawing for explaining a tiling process according to another embodiment of the present invention.

[0123] First, as shown in FIG. 8 (a), a dip adhesive material (300) can be applied to a part of the device junction (401) of the target substrate (400). At this time, the dip adhesive material (300) can be applied to the target substrate (400) using the adhesive material application method shown in FIG. 2 and FIG. 4.

[0124] Next, as illustrated in FIG. 8(b), the device (500) can be transferred to the device junction (401) coated with a bonding material (300) using various transfer processes. For example, the device (500) can be transferred using transfer processes such as laser-induced forward transfer, electrostatic transfer, fluidic-based assembly transfer, elastomer stamp transfer, roll-to-roll / R2R transfer, vacuum suction-based transfer, and electromagnetic transfer.

[0125] One or more external forces, such as heat, laser, and pressure, may be applied to the device (500) transferred onto the device junction (401) through various transfer processes. The dipped adhesive material (300) is activated by these external forces, and an electrical and physical connection may be formed between the device (500) and the device junction (401) by the activated adhesive material (300).

[0126] Next, the application of the adhesive material (200), the transfer of the device (500), and the bonding are repeated on the device bonding portion (401) where the adhesive material (200) is not applied, so that the device (500) can be transferred and bonded over the entire target substrate (400) as shown in (c) and (d) of FIG. 8.

[0127] Next, the adhesive material (200) can be applied to the device junction (401) where the adhesive material (200) is not applied, and the device (500) can be transferred and bonded over the entire target substrate (400) by repeating the application of the adhesive material (200), the transfer of the device (500), and the bonding.

[0129] FIG. 9 is a flowchart illustrating a method for dipping an adhesive material using a first dipping stamp according to an embodiment of the present invention.

[0130] Referring to FIG. 9, the adhesive material (200) is heated, and then the first dipping stamp (100) is brought into contact with the adhesive material (200) and pressed (S902).

[0131] After performing step S902, the adhesive material (200) is cooled, and then the first dipping stamp (100) is separated from the adhesive material (200) (S904).

[0132] When step S904 is performed, the adhesive material (300) is dipped into the protrusion (103) of the first dipping stamp (100) (S906). That is, when the adhesive material (200) is cooled and the first dipping stamp (100) is separated, the adhesive material (300) can be dipped into the protrusion (103) of the first dipping stamp (100).

[0133] After performing step S906, while the target substrate (400) is heated, each of the protrusions (103) on which the adhesive material (300) of the first dipping stamp (100) is dipped is brought into contact with the corresponding device junction (401) of the target substrate (400) (S908).

[0134] That is, while the target substrate (400) is heated by a heating process, the first dipping stamp (100) can be moved toward the target substrate (400) so that each of the protrusions (103) on which the adhesive material (300) is dipped is placed on the corresponding device junction (401) of the target substrate (400).

[0135] Then, the first dipping stamp (100) can be brought into contact with the target substrate (400). At this time, the target substrate (400) may be in a heated state.

[0136] Accordingly, when the first dipping stamp (100) is contacted (attached) to the heated target substrate (400), the adhesive material (300) dipped in the dipping stamp (100) can be dipped (coated) as it flows down onto the target substrate (400).

[0137] After performing step S908, the target substrate (400) and the dipped adhesive material (300) are cooled, and then the first dipping stamp (100) is separated from the target substrate (400) (S910), and the dipped adhesive material (300) is transferred to the device junction (401) of the target substrate (400) (S912). That is, when the first dipping stamp (100) is separated from the target substrate (400), the dipped adhesive material (300) can be transferred (dipped, applied) to the device junction (401).

[0138] When step S912 is performed, the device (500) is transferred to the device junction (401) of the target substrate (400) on which the adhesive material (300) is dipped using a transfer process (S914).

[0139] When step S914 is performed, the dipped adhesive material (300) is activated to electrically and physically connect the device (500) to the device junction (401), thereby electrically connecting the device (500) to the substrate base (402) (S916).

[0140] That is, when one or more of the external forces of heat, laser, and pressure are applied, the adhesive material (300) dipped into the target substrate (400) is activated, and the device (500) transferred onto the target substrate (400) can form an electrical and physical connection with the device junction (401) by means of the activated adhesive material (300). Then, the device (500) can be electrically connected to the substrate base (402) of the target substrate (400).

[0142] FIG. 10 is a flowchart illustrating a method for dipping an adhesive material using a second dipping stamp according to an embodiment of the present invention.

[0143] Referring to FIG. 10, the second dipping stamp (600) is brought into contact with the adhesive material (200) while the adhesive material is heated, and then pressure is applied (S1002).

[0144] After performing step S1002, the adhesive material (200) is cooled, and then the second dipping stamp (600) is separated from the adhesive material (200) (S1004).

[0145] When step S1004 is performed, the adhesive material (300) is dipped into the element (500) of the second dipping stamp (600) (S1006). That is, by cooling the adhesive material (200) and separating the second dipping stamp (600), the adhesive material (300) can be dipped into the element (500) of the second dipping stamp (600).

[0146] After performing step S1006, with the target substrate (400) heated, the second dipping stamp (600) is brought into contact with the target substrate (400), and then the adhesive material (300) is activated to form an electrical and physical connection between the device (500) and the device junction (401) (S1008).

[0147] That is, while the target substrate (400) is heated, the second dipping stamp (600) can be moved toward the target substrate (400) so that each of the elements (500) dipped with the adhesive material (300) is placed on the element junction (401) of the corresponding target substrate (400).

[0148] At this time, the target substrate (400) may not be heated. That is, the target substrate (400) may not be heated when heat is applied to the target substrate (400) to activate the adhesive material (300), or when a laser is irradiated onto the adhesive material (300) and its surroundings. Then, a second dipping stamp (600) is contacted (attached) to the heated target substrate (400), and one or more external forces among heat, laser, and pressure are applied to activate the adhesive material (300) dipped on the target substrate (400). Then, an electrical and physical connection can be formed between the device (500) and the device junction (401) by the activated adhesive material (300).

[0149] When step S1008 is performed, the interposer (601) of the second dipping stamp (600) is separated from the element (500) (S1010).

[0150] When step S1010 is performed, the device (500) is transferred and bonded onto the target substrate (400) (S1012).

[0152] As described above, according to one aspect of the present invention, the present invention has the effect of improving the yield and speed of transfer, bonding, and repair processes of semiconductor devices including MLCC, CMOS chip, ASIC, HBM, SoC, etc., and display devices including Micro LED, Mini LED, etc., by performing selective application of an adhesive material through dipping of an adhesive material using a stamp at a high resolution of tens of μm and within a few seconds.

[0153] In addition, according to one aspect of the present invention, by presenting a new process that enables selective coating of an adhesive material at a high resolution of tens of μm at a high process speed, the present invention can contribute to the high integration and productivity improvement of displays, wearable devices, artificial intelligence semiconductors, system semiconductors, quantum computing devices, optical communication modules, etc.

[0154] In addition, according to one aspect of the present invention, by forming protrusions (103) (or elements) within a dipping stamp in accordance with the arrangement of an element array to be bonded on a target substrate and selectively applying an adhesive material only at desired locations on the target substrate with a resolution of tens of μm, only the elements to be bonded can be selectively transferred and bonded onto the target substrate regardless of the arrangement of elements placed on a transfer substrate or a parent substrate. Furthermore, this enables the simplification of the interposer fabrication process during micro LED display production and the high integration of chiplet-based heterojunctions during semiconductor packaging.

[0155] Furthermore, according to one aspect of the present invention, when repair is required for a defective device, the invention involves fabricating a dipping stamp capable of applying an adhesive material at the single-device level and utilizing it multiple times to selectively apply the adhesive material only to the areas requiring repair on a target substrate. This eliminates the need to fabricate a new repair interposer tailored to the arrangement of defective devices to be repaired every time a repair is required. Through this, the complex processes of conventional device repair technology are simplified and process time is significantly reduced, thereby greatly improving the productivity of micro LED display fabrication and chiplet heterojunctions.

[0156] Although the present invention has been described with reference to embodiments illustrated in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom.

[0157] Therefore, the true technical scope of protection of the present invention should be determined by the following patent claims. Explanation of the symbols

[0159] 100 : 1st dipping stamp 101 : Base section 102 : Uneven parts 103 : Protrusion 200 : Adhesive material 300: Dipped adhesive material 400 : Target substrate 401: Component junction 402 : Substrate base 500 : Device 600: Second dipping stamp 601 : Interposer

Claims

Claim 1 A method for dipping an adhesive material, comprising: a step of dipping an adhesive material into a first dipping stamp; a step of transferring the adhesive material dipped into the first dipping stamp to a target substrate; and a step of transferring an element onto the target substrate on which the adhesive material has been transferred, wherein the dipping step comprises: a step of applying pressure after contacting the first dipping stamp onto the adhesive material while the adhesive material is heated; a step of separating the first dipping stamp from the adhesive material; and a step of dipping the adhesive material into a protrusion of the first dipping stamp. Claim 2 A method for dipping an adhesive material according to claim 1, wherein the first dipping stamp comprises a base portion; and an uneven portion provided on the base portion, and the uneven portion comprises at least one protrusion. Claim 3 A method for dipping an adhesive material according to claim 1, wherein the adhesive material is in the form of a film or paste and is composed of at least one of a curable resin, a reducing agent, a thermoplastic resin, a curing agent, and a solder. Claim 4 A method for dipping an adhesive material according to claim 1, characterized in that, in the step of separating the first dipping stamp from the adhesive material, the adhesive material is in a cooled state. Claim 5 A method for dipping an adhesive material according to claim 1, wherein the shape and volume of the adhesive material dipped in the first dipping stamp are determined based on at least one of the protrusion of the first dipping stamp, the surface condition of the adhesive material, the heating temperature, and the applied pressure. Claim 6 An adhesive material dipping method according to claim 1, further comprising the step of forming the adhesive material into a flat film or paste by heating or blading the separated adhesive material after the step of dipping the adhesive material into the protrusion of the first dipping stamp. Claim 7 A method for dipping an adhesive material according to claim 1, wherein the target substrate comprises: a substrate base portion; and at least one device junction portion disposed on the upper surface of the substrate base portion. Claim 8 A method for dipping an adhesive material according to claim 7, wherein the step of transferring the dipped adhesive material to a target substrate comprises: a step of contacting each of the protrusions on which the adhesive material of the first dipping stamp is dipped with the corresponding device junction of the target substrate while the target substrate is heated; a step of separating the first dipping stamp from the target substrate after cooling the dipped adhesive material and the target substrate; and a step of transferring the dipped adhesive material to the device junction. Claim 9 A method for dipping an adhesive material according to claim 8, further comprising the step of performing a surface treatment process on the target substrate prior to the step of contacting each of the protrusions dipped with the adhesive material of the first dipping stamp with the corresponding device junction of the target substrate. Claim 10 A method for dipping an adhesive material according to claim 1, wherein the step of transferring an element onto the target substrate comprises: a step of transferring the element to the element junction of the target substrate dipped with the adhesive material using a transfer process; and a step of activating the dipped adhesive material to electrically and physically connect the element to the element junction, thereby electrically connecting the element to the substrate base of the target substrate. Claim 11 A method for dipping an adhesive material, comprising: a step of dipping an adhesive material into a second dipping stamp equipped with at least one element; and a step of transferring and bonding the at least one element onto a target substrate through the adhesive material dipped into the second dipping stamp, wherein the dipping step comprises: a step of applying pressure after contacting the second dipping stamp onto the adhesive material while the adhesive material is heated; a step of separating the second dipping stamp from the adhesive material; and a step of dipping the adhesive material into the element of the second dipping stamp. Claim 12 A method for dipping an adhesive material according to claim 11, wherein the second dipping stamp comprises an interposer; and at least one element provided in the interposer, and the interposer is a substrate in which an adhesive layer is formed in the form of a film or a pattern array on at least one of Si, Glass, Quartz, and a polymer film. Claim 13 A method for dipping an adhesive material according to claim 11, wherein the adhesive material is in the form of a film or paste and is composed of at least one of a curable resin, a reducing agent, a thermoplastic resin, a curing agent, and a solder. Claim 14 A method for dipping an adhesive material according to claim 11, characterized in that, in the step of separating the second dipping stamp from the adhesive material, the adhesive material is in a cooled state. Claim 15 A method for dipping an adhesive material according to claim 11, characterized in that the shape and volume of the adhesive material dipped in the second dipping stamp are determined based on at least one of the element of the second dipping stamp, the surface condition of the adhesive material, the heating temperature, and the applied pressure. Claim 16 A method for dipping an adhesive material according to claim 11, further comprising the step of forming the adhesive material into a flat film or paste by heating or blading the separated adhesive material after the step of dipping the adhesive material into the element of the second dipping stamp. Claim 17 A method for dipping an adhesive material according to claim 11, wherein the target substrate comprises: a substrate base portion; and at least one device junction portion disposed on the upper surface of the substrate base portion. Claim 18 A method for dipping an adhesive material according to claim 11, wherein the step of transferring and bonding at least one element onto a target substrate comprises: a step of contacting each element dipped with the adhesive material of the second dipping stamp with a corresponding element bonding portion of the target substrate, and then activating the dipped adhesive material to form an electrical and physical connection between the element and the element bonding portion; and a step of transferring and bonding the element onto the target substrate by separating the interposer of the second dipping stamp from the element. Claim 19 In claim 18, the step of forming an electrical and physical connection between the device and the device junction is characterized by moving a second dipping stamp toward a target substrate to make contact so that each device dipped in the adhesive material is placed on the device junction of a corresponding target substrate, applying an external force to activate the dipped adhesive material, and electrically and physically connecting the device and the device junction by the activated adhesive material. Claim 20 A method for dipping an adhesive material according to claim 18, further comprising the step of performing a surface treatment process on the target substrate prior to the step of contacting each of the dipped elements of the second dipping stamp with the element junction of the corresponding target substrate.

Images