Microstructure transfer stamping department, transfer method, electrical equipment manufacturing method, electronic equipment manufacturing method, LED screen manufacturing method

Abstract

The invention proposes a microstructured transfer stamping device comprising a matrix and a silicone-based rubber film formed on the matrix, in which the surface of the silicone-based rubber film facing away from the matrix has one or more cavities, each cavity being closed except for the surface pores. The invention proposes a microstructured transfer stamping device capable of optimizing the transient adhesion strength of the surface of the silicone-based rubber film stamping device for short periods.

Description

Stamp parts for transferring microstructures

[0001] The present invention relates to a stamp component for transferring a minute structure by stamping.

[0002] In recent years, with the miniaturization of semiconductor elements, microstructure transfer technology using stamps has attracted attention as a means of assembling electrical and electronic products using semiconductor elements (Non-Patent Document 1). In particular, this technology has been actively developed to manufacture LED displays for signage, TVs, medical devices, in-vehicle devices, tablets, smartphones, smartwatches, and other devices, as well as for AR / VR, by transferring one, multiple, or even tens of thousands of mini-LEDs (LEDs with short sides of 100 μm or more to several hundred μm) or micro-LEDs (with short sides of 100 μm or less, or even 50 μm or less) at a time.

[0003] As semiconductor chips and various electric and electronic elements become smaller and thinner, the use of stamps to transfer microstructures is beginning to replace the conventional method of transferring elements using vacuum suction in semiconductor packaging and electronic device assembly. For example, a wide variety of microelements are being transferred, including various high-performance LSI / IC chips, tiny resistors, capacitors, inductors, SAW filter elements, MEMS chips such as acceleration sensors, and so on.

[0004] In this way, the transfer of microstructures using stamps is growing into an indispensable technology for manufacturing devices that will enrich and diversify our lives in the future.

[0005] It has been reported that a rubber stamp whose main component is silicone, such as PDMS (polydimethylsiloxane), can be used as the adhesive layer for the stamp method to transport a large number of elements from a supply substrate to a receiving substrate (Patent Document 1). Patent Document 2 shows an evolved stamp structure adapted to a chip mounting device as a more practical form of this.

[0006] Figure 20 is a structural explanatory diagram of an example of a stamp component for transferring a microstructure according to the prior art. The structure and features of an example of a conventional stamp disclosed in Patent Document 2 will be briefly described using Figure 20. In Figure 20, 41 is a quartz substrate, 42 is a silicone rubber film, 43 is a silicone rubber film, and 44 to 48 are convex portions made of a silicone rubber film provided on the surface of silicone rubber film 43.

[0007] Figure 20(a) shows a flat stamp 200 with a silicone rubber film 42 formed on a quartz substrate 41, and is used to transfer multiple or a large number of microstructures at once. Figures 20(b) to 20(f) show a silicone rubber film 43 formed on a quartz substrate 41. Convex portions 44 to 48 are provided on the surface of the silicone rubber film 43 opposite the quartz substrate 41. The stamp 200 with these convex portions is used to transfer one or multiple objects.

[0008] The object to be transferred is temporarily adhered to the surface of the silicone rubber film 42 or the uppermost surface of the convex portions of the convex portions 44-48 using the pressure-sensitive adhesive properties of the silicone rubber. After being moved to a predetermined position and brought into contact with the destination, the silicone rubber surface is peeled off from the object and placed in the predetermined location. For example, by applying a resin or the like having a stronger adhesive strength than the temporary adhesive strength of the silicone rubber film surface to the destination surface, the object can be received at the destination surface and the surface of the silicone rubber film 42 or the uppermost surface of the convex portions of the convex portions 44-48 can be peeled off from the object. The temporary adhesive strength of the silicone rubber film surface, which determines the transfer capability, is primarily a pressure-sensitive adhesive strength and depends on the hardness, surface adhesion, tack, etc. of the silicone rubber film. Therefore, the physical properties of the silicone rubber film must be adjusted and optimized to meet the requirements of the size, surface morphology, weight, and other characteristics of the object to be transferred, as well as process conditions such as the transfer speed and acceleration of the transfer device.

[0009] US Patent No. 7,943,491 JP 2020-129638 A

[0010] Matthew A. Meitl, Zheng-Tao Zhu, Vipan Kumar, Keon Jae Lee, Xue Feng, Yonggang Y. Huang, Ilesanmi Adesida, Ralph G. Nuzzo & John A. Rogers, “Transfer printing by kinetic control of adhesion to an elastomeric stamp”, Nature Materials Volume 5, 33-38 (2006).

[0011] However, with the above-mentioned configuration, when optimizing the temporary adhesive strength of the silicone rubber film stamp surface, it is extremely difficult and time-consuming to optimize the physical properties of the silicone rubber film to meet the requirements of the object to be transferred and the transfer conditions.

[0012] The present invention has been made to solve the above-mentioned problems, and aims to provide a stamp part for transferring microstructures that can optimize the temporary adhesive strength of the silicone-based rubber film stamp surface in a short period of time.

[0013] In order to solve the above problem, the first invention of the present invention provides a stamp part for transferring microstructures, characterized in that a silicone-based rubber film is formed on a substrate, and the surface of the silicone-based rubber film opposite the substrate has one or more recesses that are closed except for the surface opening.

[0014] In this way, by using a silicone rubber film with a pressure-sensitive adhesive strength greater than the required temporary adhesive strength and forming one or more closed recesses on its surface, it is possible to reduce the surface area of ​​contact between the silicone rubber film and the microstructure to be transferred. As a result, there is no need to perform delicate optimization of the pressure-sensitive adhesive strength (which depends on the hardness, surface adhesion, tack, etc. of the silicone rubber) through synthetic optimization to change the physical properties of the silicone rubber film. Instead, it is possible to optimize the temporary adhesive strength of the surface that comes into contact with the microstructure by design changes that optimize the shape, opening area (size and number), and layout of the closed recesses. In other words, according to the first aspect of the present invention, a stamp component for transferring microstructures can be provided that can quickly optimize the temporary adhesive strength of the silicone rubber film stamp surface. Furthermore, the stamp component of the present invention can be used to transfer not only one microstructure, but multiple or numerous microstructures at once.

[0015] Furthermore, by doing this, when the microstructure and the silicone rubber film surface including the closed recess are temporarily bonded, the closed recess becomes a closed space. Since the temporary bonding is performed with an optimized pressing amount, the closed space of the closed recess becomes a decompressed state at the stage of temporary bonding. As a result, when the volume of the recess space is small, a weak suction force acts on the microstructure, which stabilizes the bonding state.

[0016] The surface opening shape of the closed recess can be, for example, a shape selected from the group consisting of a circle, an ellipse, a ring, and a polygon.

[0017] The surface opening of the closed recess may have any shape as long as it is a closed shape.

[0018] The depth of the closed recessed portion may be such that it does not reach the substrate.

[0019] In this way, the silicone rubber film and the substrate are bonded together over the entire surface, improving durability and reducing the frequency of replacement of the stamp component of the present invention, thereby improving productivity in transferring microstructures.

[0020] A plurality of the closed recesses may be arranged in a matrix on the surface of the silicone rubber film.

[0021] In this way, the minute structure and the temporary adhesion surface of the silicone rubber surface including the closed recess can be adhered and held with a uniform force.

[0022] A plurality of the closed recesses may be arranged in a geometric pattern on the surface of the silicone rubber film.

[0023] In this way, closed recesses can be formed with an optimal layout that matches the shape of the temporary adhesion surface of the microstructure that is the adherend.

[0024] The surface of the silicone rubber film may have a lattice pattern in the areas other than the closed recesses.

[0025] In this way, large recess surface openings can be formed, so that even when using a silicone-based rubber with very strong pressure-sensitive adhesive strength, or especially very strong adhesive strength, the opening area (size and number) of the recesses can be optimized to achieve the desired relatively weak temporary adhesive strength.

[0026] The portion of the surface of the silicone rubber film other than the closed recesses may have a cross-sectional pattern of a honeycomb structure.

[0027] In this case, as with the grid pattern, the surface to be temporarily bonded to the microstructure has a regular layout, so that a uniform temporary adhesive force is generated on the temporary bonding surface of the microstructure, thereby providing stable transfer operations.

[0028] In the surface of the silicone rubber film, the closed recess may include at least an annular recess.

[0029] In this way, when a minute structure having a surface with good symmetry, such as a square or a circle, is temporarily bonded, a stable temporary adhesive force can be exerted.

[0030] The closed recess may include a first closed recess and a second closed recess having different surface opening areas, and the surface opening area of ​​the second closed recess may be smaller than the surface opening area of ​​the first closed recess.

[0031] In this way, the adhesive area with the microstructure can be controlled by both the first closed recess and the second closed recess having a surface opening area smaller than that of the first closed recess. That is, the adhesive strength can be roughly adjusted by the relatively large first closed recess, and the adhesive area and adhesive strength can be finely adjusted by the second closed recess having a surface opening area smaller than that of the first closed recess. Furthermore, when the opening depth of the second closed recess having a surface opening area smaller than that of the first closed recess is minute, a suction force, albeit weak, acts on the microstructure in the closed space formed by the adhesive surface between the second closed recess having a surface opening area smaller than that of the first closed recess and the microstructure, as described above in relation to the surface opening shape of the closed recess, and therefore the adhesive state can be stabilized.

[0032] In addition, the second invention of the present invention provides a stamp component for transferring microstructures, characterized in that a silicone-based rubber film is formed on a substrate, one or more convex portions are formed on the surface of the silicone-based rubber film opposite the substrate, and the surface of the convex portion has one or more concave portions that are closed except for the surface opening.

[0033] In this way, by optimizing the shape, opening area (size and number), and layout of the closed recesses provided on the surface of the convex portion, the temporary adhesive strength of the silicone rubber film surface on which the convex portion that contacts the microstructure is provided can be optimized. That is, according to the second aspect of the present invention, a stamp component for transferring microstructures can be provided that can optimize the temporary adhesive strength of the silicone rubber film stamp surface in a short period of time. Furthermore, by using the stamp component of the present invention, one to a large number of microstructures can be selectively removed from a specific area from a supply section where many microstructures are densely arranged without contacting adjacent microstructures.

[0034] Furthermore, in this way, when the microstructure and the surface of the convex portion including the closed recess are temporarily bonded, the closed recess becomes a closed space. Since the temporary bonding is performed with an optimized pressing amount, the closed space of the closed recess becomes a decompressed state at the stage of temporary bonding. As a result, when the volume of the recess space is small, a weak suction force acts on the microstructure, making it possible to stabilize the bonding state.

[0035] The convex portion may include a convex-shaped protrusion having two or more steps, and the uppermost surface of the convex-shaped protrusion having two or more steps may have one or more closed recesses.

[0036] In this way, by optimizing the shape, opening area (size and number), and layout of the closed recesses provided on the uppermost surface of the two or more step convex-shaped protrusions, the temporary adhesive strength of the silicone rubber film surface on the uppermost surface of the two or more step convex-shaped protrusions that contact the microstructure can be optimized. Furthermore, by using such a stamp component, it is possible to selectively extract one or a specific region of a microstructure from a supply unit where many microstructures are densely arranged, even for even smaller microstructures, without contacting adjacent microstructures.

[0037] The closed recess preferably has a curved bottom surface.

[0038] In this way, the entire bottom surface of the closed recess is temporarily bonded to the microstructure, and the entire closed recess is placed in a vacuum state. As a result, the shape restoration force of the closed recess exerts an adhesive force on the adhesive surface, making it possible to temporarily bond the microstructure even if the adhesive strength of the silicone rubber film is weak. Note that if the adhesive strength of the silicone rubber film is strong, this can be easily adjusted by reducing the adhesive area of ​​the convex portion.

[0039] For example, the bottom surface of the closed recess may be spherical or aspherical.

[0040] In this way, the minute structure and the bottom surface of the closed recess formed on the surface of the convex portion can be temporarily bonded with only a small deformation.

[0041] For example, the surface opening shape of the closed recess may be a circle or an ellipse.

[0042] In this way, the shape of the bottom surface of the closed recess can be made to be a part of the surface of a sphere or a part of the surface of an ellipse.

[0043] When the surface opening of the closed recess is polygonal, the vertices of the polygon may preferably be arc-shaped.

[0044] In this way, the inflection point of the angle of the vertex can be eliminated, thereby improving the vacuum holding ability when bonding the surface of the microstructure to the bottom surface of the closed recess formed on the surface of the convex portion.

[0045] Preferably, a plurality of the convex portions are formed on the surface of the silicone rubber film, and the plurality of convex portions are arranged in a matrix at a constant pitch in both the X direction and the Y direction.

[0046] For example, in the case of electrical and electronic devices or 3D packages, microstructures can be transferred and mounted simultaneously in a regular layout. In the case of a microLED display, by forming a matrix with the display pixel pitch of the display, microLEDs can be transferred and mounted on a backplane substrate all at once. This is extremely useful when arranging microstructures in a matrix at a predetermined desired pitch.

[0047] The convex portion may be in the form of a cylinder, a polygonal prism, a frustum, or a multi-step shape that is a combination of these.

[0048] As the pitch of the matrix becomes smaller, it becomes necessary to make the convex portions smaller so as not to interfere with adjacent microstructures. In this case, the problem of reduced mechanical strength of the convex portions arises. In order to increase the mechanical strength of the convex portions without reducing their height, this can be solved by gradually reducing the size (width, thickness) of the protrusions while keeping the height the same. In this case, the convex portions can be realized by combining columnar or frustum shapes.

[0049] The cross-sectional shape of the convex portion in the height direction may be a shape that convex inward.

[0050] If the cross-sectional shape of the convex portion in the height direction, i.e., the cross-sectional profile of the plane perpendicular to the substrate, is a shape that convex toward the inside of the convex portion, it is easy to avoid interference with adjacent chips. This is suitable for relatively large convex portions.

[0051] Alternatively, the cross-sectional shape of the convex portion in the height direction may be a shape that convex outward.

[0052] This is effective in obtaining mechanical strength for relatively small convex-shaped protrusions.

[0053] It is preferable that a conductive film is formed between the substrate and the silicone rubber film.

[0054] In this way, when transferring a microstructure using the stamp component of the present invention, the electrostatic adsorption of particles such as dust generated within the transfer machine can be suppressed compared to when no conductive film is used.

[0055] Alternatively, it is more preferable that the silicone rubber film is a conductive film.

[0056] In this way, it is possible to omit the step of forming an extra conductive film, and also to suppress the electrostatic adsorption of particles such as dust generated inside the transfer machine.

[0057] For example, the substrate may be a quartz substrate.

[0058] It is more preferable that the quartz substrate is a synthetic quartz substrate.

[0059] When a synthetic quartz substrate is used, the flatness of the substrate is dramatically improved, which in turn greatly improves the surface flatness of the silicone rubber film, resulting in a dramatic improvement in the transfer performance of the microstructure transfer device.

[0060] Alternatively, the substrate may be a sapphire substrate.

[0061] In this way, the mechanical strength is higher than that of a quartz (including synthetic quartz) substrate, and therefore a stamp component for transferring a minute structure having excellent durability can be provided.

[0062] Alternatively, the substrate may be a silicon wafer or a silicon wafer fragment.

[0063] In this way, it is possible to provide a stamp component for transferring a microstructure that is even more excellent in flatness than a synthetic quartz substrate.

[0064] As described above, the stamp component for transferring microstructures according to the first aspect of the present invention has a silicone rubber film formed on a substrate, and the surface of the silicone rubber film opposite the substrate has one or more recesses that are closed except for the surface openings. This allows the adhesive strength (adhesion and tack) of the silicone rubber film to be adjusted and optimized not only by adjusting the film composition but also by adjusting the opening area (size and number) of the closed recesses and the pattern layout. In other words, according to the first aspect of the present invention, a stamp component for transferring microstructures can be provided that can quickly optimize the temporary adhesive strength of the silicone rubber film stamp surface. Furthermore, by having one or more recesses that are closed except for the surface openings, the suction force generated by the reduced pressure in the closed recesses can also be used as a control factor for the temporary adhesive strength of the stamp.

[0065] The second invention of the present invention, a stamp component for transferring a microstructure, has a silicone-based rubber film formed on a substrate, and one or more convex portions formed on the surface of the silicone-based rubber film opposite the substrate. The surface of the convex portion has one or more concave portions that are closed except for the surface opening, so that microstructures can be temporarily attached and transferred using one or more convex portions. Having only one convex portion is useful for repair. On the other hand, it is also possible to transfer multiple microstructures at once using multiple convex portions. It is also possible to transfer multiple microstructures at once using each convex portion. Furthermore, by arranging the convex portions in a matrix format according to the desired pattern layout of the transfer destination, for example, in the case of a display, at the pixel pitch, it is possible to transfer them all at once to the desired pattern layout.

[0066] Furthermore, the temporary adhesive strength can be adjusted and optimized by adjusting the adhesive strength (adhesion and tackiness) derived from the film composition on the surface of the convex portion made of a silicone rubber film and the area (size and number) of the closed recesses. That is, according to the second aspect of the present invention, a stamp component for transferring a microstructure can be provided that can optimize the temporary adhesive strength of the silicone rubber film stamp surface in a short period of time. Furthermore, the stamp component for transferring a microstructure of the present invention is effective when microstructures are densely arranged or when several microstructures on the supply substrate side are transferred at once.

[0067] A stamp part for transferring microstructures, which is one embodiment of the second invention of the present invention, has a convex portion that includes a convex-shaped protrusion with two or more stages, and the uppermost surface of the convex-shaped protrusion with two or more stages has one or more closed recesses, thereby providing the mechanical strength of the convex portion required for transfer and durability during the transfer operation even when the size of the microstructure is on the order of 100 μm, or even on the order of 10 μm.

[0068] In another embodiment of the second invention of the present invention, the stamp component for transferring a microstructure has a closed recess with a curved bottom surface, so that when the microstructure is temporarily bonded, the bottom surface of the closed recess can be bonded to the bonding surface of the microstructure without any gaps. As a result, the adhesive force of the closed recess can be maximized, and even if the adhesive surface is small, a large temporary adhesive force can be generated in addition to the adhesive force of the silicone rubber film.

[0069] In this way, by providing closed recesses on the surface of the silicone rubber film or the surface of the convex portion that is temporarily bonded to the microstructure, it is possible to significantly improve the adjustment window for the adhesive strength of a single silicone rubber film by adjusting not only the composition and physical properties of the silicone rubber film but also the shape, opening area (size and number), layout, and adhesive strength of the closed recesses, which can greatly contribute to improving industrial productivity.

[0070] FIG. 1 is a structural explanatory diagram of an example of a stamp component for transferring a microstructure according to a first embodiment of the present invention; FIG. 2 is an explanatory diagram of the effect of a closed recess of an example of a stamp component for transferring a microstructure according to the first embodiment of the present invention; FIG. 3 is a structural explanatory diagram of another example of a stamp component for transferring a microstructure according to the first embodiment of the present invention; FIG. 4 is a structural explanatory diagram of another example of a stamp component for transferring a microstructure according to the first embodiment of the present invention; FIG. 5 is a structural explanatory diagram of an example of a stamp component for transferring a microstructure according to a second embodiment of the present invention; FIG. 6 is a structural explanatory diagram of another example of a stamp component for transferring a microstructure according to the second embodiment of the present invention; FIG. 7 is a structural explanatory diagram of another example of a stamp component for transferring a microstructure according to the third embodiment of the present invention; FIG. 8 is a structural explanatory diagram of a stamp component for transferring a microstructure according to a fourth embodiment of the present invention; FIG. 9 is a structural explanatory diagram of a stamp component for transferring a microstructure according to a fifth embodiment of the present invention; FIG. 10 is a structural explanatory diagram of a stamp component for transferring a microstructure according to a sixth embodiment of the present invention; FIG. 11 is a structural explanatory diagram of a stamp component for transferring a microstructure according to a seventh embodiment of the present invention; FIG. 12 is a structural explanatory diagram of a stamp component for transferring a microstructure according to an eighth embodiment of the present invention; Fig. 10 is a structural explanatory diagram of a stamp component for transferring a microstructure showing a tenth embodiment of the present invention; Fig. 11 is a structural explanatory diagram and an operational explanatory diagram of a stamp component for transferring a microstructure showing an eleventh embodiment of the present invention; Fig. 12 is a structural explanatory diagram of a stamp component for transferring a microstructure showing a twelfth embodiment of the present invention; Fig. 13 is a structural explanatory diagram of a stamp component for transferring a microstructure showing a thirteenth embodiment of the present invention; Fig. 14 is a structural explanatory diagram of a stamp component for transferring a microstructure showing a fourteenth embodiment of the present invention; Fig. 15 is a structural explanatory diagram of an example of a stamp component for transferring a microstructure of prior art;

[0071] As mentioned above, there was a need for the development of stamp parts for transferring microstructures that could optimize the temporary adhesive strength of the silicone rubber film stamp surface in a short period of time.

[0072] As a result of extensive research into the above-mentioned problems, the inventors discovered that by providing closed recesses on the surface of the silicone rubber film or on the surface of the convex portion that is temporarily bonded to the microstructure, it is possible to significantly improve the adjustment window for the adhesive strength of a single silicone rubber film by adjusting not only the composition and physical properties of the silicone rubber film but also the shape, opening area (size and number), layout, and adhesive strength of the closed recesses, and thus completed the present invention.

[0073] In other words, the present invention is a stamp part for transferring microstructures, characterized in that a silicone-based rubber film is formed on a substrate, and the surface of the silicone-based rubber film opposite the substrate has one or more recesses that are closed except for the surface opening.

[0074] The present invention also provides a stamp component for transferring microstructures, characterized in that a silicone-based rubber film is formed on a substrate, one or more convex portions are formed on the surface of the silicone-based rubber film opposite the substrate, and the surface of the convex portion has one or more concave portions that are closed except for the surface opening.

[0075] The present invention will be described in detail below, but the present invention is not limited thereto.

[0076] (First Embodiment) FIG. 1 is a structural explanatory diagram of an example of a stamp component for transferring a microstructure according to a first embodiment of the present invention. FIG. 1(a) is a cross-sectional view of the stamp component for transferring a microstructure 100, and FIG. 1(b) is a top view of the stamp component for transferring a microstructure 100. The cross-sectional view (a) shows the cross-sectional structure taken along the line P-Q in the top view (b). In FIG. 1, 1 denotes a substrate (e.g., a quartz substrate), 2 denotes a silicone-based rubber film, and 3 denotes a closed recess formed on the surface 2a of the silicone-based rubber film 2 (the surface of the silicone-based rubber film opposite the substrate 1). As shown in FIG. 1, the closed recess 3 is closed except for a surface opening 3a. Furthermore, as shown in FIG. 1(b), a plurality of closed recesses 3 are arranged in a matrix on the surface 2a of the silicone-based rubber film.

[0077] 1B illustrates a case where the surface opening shape of the closed recess 3 is square. The surface opening shape of the closed recess 3 is not limited to a square, and may be any closed shape such as a circle, an ellipse, a ring, or a polygon such as a triangle, a rectangle (rectangle), or a hexagon.

[0078] FIG. 2 is an explanatory diagram illustrating the effect of a closed recess in an example of a stamp component for transferring a microstructure according to the first embodiment of the present invention. In FIG. 2, (a) is a bottom view of only the stamp component for transferring a microstructure 100 of this example, and (b) and (c) are cross-sectional views. Cross-sectional views (b) and (c) show a cross-section of the P-Q portion of the bottom view (a), illustrating a state in which a microstructure 4 is temporarily bonded to the silicone-based rubber film surface 2a. FIG. 2(b) illustrates the case of a microstructure 4 having a surface smaller than the surface 2a of the silicone-based rubber film 2, while FIG. 2(c) illustrates the case of a microstructure 4 having a surface larger than the surface 2a of the silicone-based rubber film 2. The stamp component for transferring a microstructure 100 shown in FIG. 2 is similar to the stamp component for transferring a microstructure 100 shown in FIG. 1.

[0079] The effect of the closed recess 3 will be explained using Figure 2 (b). If the adhesive area between the silicone rubber film 2 and the microstructure 4 is S and the total surface area of ​​the closed recess 3 is A, then the actual temporary adhesive area is (S - A). In general, with a silicone rubber film, the temporary adhesive strength is mainly derived from adhesive strength and pressure-sensitive adhesive strength. That is, the temporary adhesive strength is the sum of the adhesive strength of the surface 2a of the silicone rubber film 2 and the tack force that is generated depending on the amount of displacement of the silicone rubber surface 2a when the microstructure 4 and the silicone rubber film 2 are pressure-bonded. Because the temporary adhesive strength is generated at the temporary adhesive surface between the silicone rubber film 2 and the microstructure 4, the temporary adhesive strength is highly dependent on the temporary adhesive area S.

[0080] In Figure 2, the transfer of one microstructure 4 is shown as an example to explain the effect of the closed recess 3, but even when transferring multiple microstructures at once, the temporary adhesive force can be adjusted by adjusting the shape, opening area (size and number), and layout of the closed recess, taking into account the effect of the similar temporary adhesive area.

[0081] 3A and 3B are explanatory diagrams showing the structure of closed recesses in another example of the stamp component for transferring a microstructure according to the first embodiment of the present invention. FIG. 3A is a cross-sectional view of the stamp component for transferring a microstructure 100 of this example, and FIG. 3B is a top view. The cross-sectional view (a) shows the cross-sectional structure between P-Q in the top view (b). The difference from FIG. 2 is the layout of the closed recesses 3; in FIG. 3, the matrix pattern of the closed recesses 3 is rotated 45 degrees from that in FIG. 2.

[0082] FIG. 4 is an explanatory diagram of the structure of closed recesses in another example of the stamp component for transferring microstructures according to the first embodiment of the present invention. FIG. 4(a) is a cross-sectional view of the stamp component for transferring microstructures 100 of this example, and FIG. 4(b) is a top view. The cross-sectional view (a) shows the cross-sectional structure between P-Q in the top view (b). The difference from FIG. 2 is that multiple closed recesses 5, each with a circular surface opening, are formed on the silicone rubber film surface 2a, and the layout of the closed recesses 5 is different. In FIG. 4, the closed recesses 5 are laid out on a concentric hexagonal pattern. By arranging the closed recesses 5 in this manner in a geometric pattern, it is possible to construct a regular pattern layout with several symmetries.

[0083] In the present invention, when the microstructure and the silicone rubber surface including the closed recess are temporarily bonded, the closed recess becomes a closed space. Since the temporary bonding is performed with an optimized pressing force, the closed space of the closed recess becomes a decompressed state at the stage of temporary bonding. As a result, when the volume of the recess space is small, a weak suction force acts on the microstructure, which stabilizes the bonded state.

[0084] Also, as in the examples shown in FIGS. 1 to 4, it is preferable that the depth of the closed recess does not reach the substrate.

[0085] In this way, the silicone rubber film and the substrate are bonded together over the entire surface, improving durability and reducing the frequency of replacement of the stamp component of the present invention, thereby improving productivity in transferring microstructures.

[0086] Second Embodiment A second embodiment of the present invention will now be described with reference to the drawings. Fig. 5 shows an explanatory structural diagram of an example of a stamp component 100 for transferring a microstructure according to the second embodiment of the present invention. Fig. 5(a) is a cross-sectional view, and Fig. 5(b) is a top view.

[0087] The difference from the first embodiment is that the size of the surface openings 6a of the closed recesses 6 is relatively large. In this case, if we look at the portions 2b of the surface 2a of the silicone rubber film 2 other than the closed recesses 6 rather than the closed recesses 6, the remaining portions 2b of the silicone rubber film surface 2a form a lattice pattern, as shown in Figure 5(b). The structure of the stamp component 100, which has a large total opening area of ​​the closed recesses 6, is suitable for use with a silicone rubber film 2 having a stronger pressure-sensitive adhesive force or adhesive strength than the optimal value when no closed recesses 6 are present. In this case, optimizing the opening area (size and number) of the closed recesses 6 can easily optimize the desired temporary adhesive strength. In other words, even when a silicone rubber film 2 having a strong pressure-sensitive adhesive force or strong adhesive strength is used, the second embodiment of the present invention allows the temporary adhesive strength of the silicone rubber film 2 to be adjusted over a fairly wide range.

[0088] Figure 6 shows an explanatory structural diagram of another example of a stamp part 100 for transferring a microstructure according to a second embodiment of the present invention. Figure 6(a) is a cross-sectional view, and Figure 6(b) is a top view. The difference from Figure 5 is that the surface opening shape of the closed recess 6 in Figure 5 is square, whereas the surface opening shape of the closed recess 7 in Figure 6 is rectangular. By changing the shape in this way, the total area of ​​the closed recesses can also be adjusted.

[0089] FIG. 7 is a structural explanatory diagram of another example of a stamp part 100 for transferring a microstructure according to a second embodiment of the present invention. FIG. 7(a) is a cross-sectional view, and FIG. 7(b) is a top view. The pattern layout of closed recesses 8 in FIG. 7 is a type of lattice pattern, in which the pattern of closed recesses 7 in FIG. 6 is all rotated by θ. Further increasing θ makes it possible to create a layout pattern in which closed recesses are connected, i.e., a zigzag pattern and a horizontally aligned recess. Therefore, these layout patterns can be considered derivative layouts of a lattice pattern.

[0090] 5 to 7, the cross-sectional view (a) shows the cross-sectional structure between PQ in the top view (b).

[0091] Even in the case of a grid-like recess pattern layout as in the second embodiment of the present invention, a closed space is formed between the closed recess and the microstructure when the silicone rubber film is temporarily attached. When the pattern size is large or the pattern depth is deep, the volume of the closed space is large and the suction effect on the microstructure is small, but as the pattern size is reduced, the volume of the closed space decreases and a suction effect on the microstructure can be expected.

[0092] The portions of the surface of the silicone rubber film other than the closed recesses may have a cross-sectional pattern of a honeycomb structure.

[0093] In this case, as with the grid pattern, the surface to be temporarily bonded to the microstructure has a regular layout, so that a uniform temporary adhesive force is generated on the temporary bonding surface of the microstructure, thereby providing stable transfer operations.

[0094] As described above, when a microstructure and a silicone-based rubber surface containing the recesses are temporarily bonded, if the area of ​​the closed recesses is small and a closed space with a small volume is formed, the closed space of the closed recesses becomes decompressed when the microstructure is temporarily bonded with an optimized pressing force, and suction force acts on the microstructure. Although the force generated by each closed recess is weak, it can become large if there are an extremely large number of them. Therefore, it is possible to control both the effect of weakening the pressure-sensitive adhesive force by providing closed recesses and the effect of strengthening the adhesive force by the suction force of the closed recesses. Furthermore, the suction force of the closed recesses also has the effect of stabilizing the adhesive state.

[0095] The stamp component of the second embodiment of the present invention is applicable to the transfer of microstructures of any size, but is particularly suited to transferring microstructures that are the same size as or larger than the silicone rubber film that serves as the stamp, for example, when mounting relatively large thin-film chips such as semiconductor LSIs.

[0096] (Third embodiment) Figure 8 shows an explanatory diagram of the structure of a stamp component 100 for transferring a microstructure according to a third embodiment of the present invention. Figure 8(a) is a cross-sectional view, and Figure 8(b) is a top view. The cross-sectional view (a) shows the cross-sectional structure between P-Q in the top view (b).

[0097] In Figure 8, 9 denotes a closed recess whose surface opening is annular in shape, and is a concentric ring-shaped recess. There may be one or more ring-shaped (annular) closed recesses 9. The important point of this embodiment is that the recesses 9 are closed except for the surface openings. If the ring width of the closed recesses 9 is small, suction force at the recesses 9 can be expected. To further enhance this effect, it is also important to optimize the depth of the closed recesses 9. In other words, it is important to set the depth so that a reduction in the volume of the recess leads to the generation of suction force.

[0098] Although FIG. 8 shows a recess 3 in the center whose surface opening is circular and closed, in the embodiment of the present invention, the circular recess in the center may or may not be present.

[0099] Fourth Embodiment FIG. 9 is a structural explanatory diagram of a stamp component 100 for transferring a minute structure according to a fourth embodiment of the present invention.

[0100] 9(a) and 9(b), reference numerals 6 and 9 denote first closed recesses provided on the surface 2a of the silicone rubber film 2. Reference numeral 11 denotes a second recess, which is provided in a portion of the silicone rubber film surface 2a other than the first closed recess 6 or 9 and has a smaller diameter (surface opening area) than the first closed recess 6 or 9. The second recess 11 is also a recess whose entire surface is closed except for the surface opening. In an embodiment of the present invention, for example, the temporary adhesive strength can be roughly adjusted using the first closed recess, and the temporary adhesive strength can be finely adjusted using the second closed recess.

[0101] FIG. 9C is a structural explanatory diagram of a modified example of the stamp component for transferring a minute structure according to the fourth embodiment of the present invention.

[0102] In Figure 9(c), 11a denotes a recess provided on the surface 2a of the silicone rubber film, similar to the second recess 11 shown in Figures 9(a) and 9(b), with the surface closed except for the surface opening. Also, in Figure 9(c), 10 denotes a groove-shaped recess provided on the surface 2a of the silicone rubber film in a portion other than the closed recess 11a. Figure 9(c) shows a state in which the groove direction of the recess 10 is rotated by θ degrees with respect to one side of the silicone rubber film 2. The value of θ may be any angle between 0 and 360 degrees. The internal shape of the recess 10 may be wavy or zigzag, and may have any layout shape.

[0103] (Fifth embodiment) Figure 10 shows an explanatory diagram of the structure of a stamp component 100 for transferring a microstructure according to a fifth embodiment of the present invention. Figure 10(a) is a cross-sectional view, and Figures 10(b) and (c) are top views. The cross-sectional view (a) shows the cross-sectional structure between P-Q in the top view (b). Figure 10(c) is an enlarged view of a portion of Figure 10(b).

[0104] In Figure 10, reference numeral 12 denotes a convex portion provided on the surface 2a of the silicone rubber film 2. The convex portion 12 is made of the same silicone rubber film as the silicone rubber film 2. Reference numeral 13 denotes a closed recess provided on the surface 12a of the convex portion. As shown in Figure 10(c), the closed recess 13 is closed except for a surface opening 13a.

[0105] As shown in FIG. 10 , a microstructure transfer stamp component 100 having only one convex portion 12 is useful for transferring a single very small microstructure, such as a microstructure on the order of millimeters, 100 μm, or even 10 μm. In this case, the size of the surface 12 a of the convex portion 12, i.e., the adhesive surface, may be formed to be approximately the same size as the microstructure. It is preferable to make it slightly larger than the size of the microstructure. This stabilizes the adhesive strength around the periphery of the microstructure. While this depends on the positional accuracy of the transfer device, in the case of microstructures between 10 μm and 100 μm, it is preferable to make the size of the surface 12 a of the convex portion 12 larger enough to absorb errors in the positional accuracy of the transfer device.

[0106] By using the stamp of this embodiment, the temporary adhesive strength of the convex portion 12 that actually adheres to the microstructure can be optimized by adjusting the size (opening area, depth), number, and layout of the closed recesses 13 provided on the convex portion surface 12a.

[0107] In this case, the stability of the temporary adhesion between the adhesive surface of the microstructure and the surface 12a of the convex portion can be improved by adjusting the closed recess 13 formed on the surface 12a of the convex portion so that a suction force is generated by the closed recess 13.

[0108] Furthermore, by using the stamp part 100 for transferring microstructures of this embodiment, it is possible to selectively remove one or a specific area of ​​microstructures from a supply section where many microstructures are densely arranged without contacting adjacent microstructures, and it is possible to place them in a closer position to the supply side.

[0109] The stamp component 100 for transferring a minute structure having one convex portion 12 according to the fifth embodiment of the present invention is useful when transferring minute structures one by one, and is particularly essential when used for repair.

[0110] (Sixth embodiment) Figure 11 is an explanatory diagram of the structure of a stamp component 100 for transferring a microstructure according to a sixth embodiment of the present invention. Figures 11(a), (e), and (f) are cross-sectional views, and Figures 11(b) to (d) are top views. The cross-sectional view (a) shows the cross-sectional structure between P-Q in the top view (b). Figures 11(c) and (d) are enlarged views of different portions of Figure 11(b). Figure 11(e) shows the cross-sectional structure between R-S in Figure 11(c). Figure 11(f) shows the cross-sectional structure between R' and S' in Figure 11(d).

[0111] In Figure 11, 14 denotes a convex portion provided on the surface 2a of the silicone rubber film 2, and shows a case where two or more convex portions are provided. The convex portion 14 is made of the same silicone rubber film as the silicone rubber film 2. 15 denotes a closed recess portion provided on the surface 14a of the convex portion 14. As shown in Figures 11(c) and (d), the closed recess portion 15 is closed except for a surface opening 15a.

[0112] 11(c) and (e) show examples where one closed recess 15 is provided on the convex portion 14. In contrast to this, Figures 11(d) and (f) show examples where two or more closed recesses 15 are provided on the convex portion 14. In both cases of Figures 11(c) and (d), the temporary adhesive strength can be easily adjusted by optimizing the design of the size and number of the convex portion 14 and the size and number of the closed recesses 15.

[0113] 11 illustrates 49 convex portions 14 (7 × 7 matrix) because it is not easy to physically illustrate them, but if each convex portion 14 is miniaturized to form a stamp component 100 having thousands or tens of thousands of convex portions 14, the size and spacing of the convex portions 14 will inevitably be on the order of microns. It is easily conceivable that the size of the closed recesses 15 provided on the surfaces 14a of the micron-order convex portions 14 will also naturally be smaller than the scale of the convex portions 14. By using a stamp configured in this manner, the suction force of the closed recesses 15 can be fully utilized even when transferring and mounting many microstructures at once, thereby achieving stable transfer and mounting.

[0114] Seventh Embodiment Figure 12 is a structural explanatory diagram of a stamp part 100 for transferring a microstructure according to a seventh embodiment of the present invention. Figure 12(a) shows a cross-sectional structure of a first example of the stamp part 100 for transferring a microstructure, and Figure 12(b) is a top view of the convex part 12 shown in Figure 12(a). Figure 12(c) shows a cross-sectional structure of a second example of the stamp part 100 for transferring a microstructure, and Figure 12(d) is a top view of the convex part 12 shown in Figure 12(c).

[0115] In Fig. 12, 16 denotes a first convex-shaped protrusion provided on the surface of the silicone rubber film 2, and 17 denotes a second convex-shaped protrusion provided on the first convex-shaped protrusion 16. The convex portion 12 shown in Fig. 12 includes a first convex-shaped protrusion 16 and a second convex-shaped protrusion 17 at the top. That is, the convex portion 12 shown in Fig. 12 has a protrusion structure having a two-stage convex shape (two-stage convex protrusion). The first convex-shaped protrusion 16 and the second convex-shaped protrusion 17 are made of the same silicone rubber film as the silicone rubber film 2. 18 denotes a closed recess provided on the surface of the second convex-shaped protrusion 17.

[0116] 12(a) and (b) shows a first example in which first convex projections 16 are provided on the surface 2a of the silicone rubber film 2, and second convex projections 17 are provided on the convex projections 16, resulting in a single two-stage convex portion 12. On the other hand, FIGS. 12(c) and (d) show a two-stage convex portion 12 in which second convex projections 17 are formed in a 3×3 matrix on one first convex projection 16.

[0117] As shown in the fifth embodiment, by using a stamp component 100 having one convex portion 12 as shown in FIG. 10 , it is possible to selectively remove one or a specific region of microstructures from a supply section where many microstructures are densely arranged without contacting adjacent microstructures, allowing for closer placement relative to the supply side. However, as the size of the microstructures approaches the order of 100 μm, or even 10 μm, the size of the adhesive surface of the convex portion of the stamp component must be approximately the same as that of the microstructure. For example, a convex portion with an adhesive surface of 50 μm may need to be 50 μm or even twice that height to avoid interference with adjacent microstructures. In such cases, the convex portion is prone to bending, breaking, or other damage during stamp pressing due to repeated use. To address such issues, a two-stage convex portion structure, as shown in the seventh embodiment, can be used to improve strength and durability.

[0118] In addition, a stamp component for transferring microstructures having convex-shaped protrusions such as those in this embodiment is effective when microstructures are densely arranged or when several microstructures on the supply substrate are transferred at once.

[0119] As shown in Figures 12(c) and (d), the durability of the stamp can also be improved by providing a structure with two or more second protrusions 17, which are a relatively small number that can cause durability issues.

[0120] Eighth Embodiment Figure 13 is an explanatory diagram of the structure of a stamp component 100 for transferring a microstructure according to an eighth embodiment of the present invention. In Figure 13, 19 denotes a convex portion formed on the surface 2a of the silicone rubber film 2, and 20 denotes a closed recess provided on the surface 19a of the convex portion 19. Figure 13(a) is a cross-sectional view of this embodiment, and Figure 13(b) is a top view of this embodiment. The cross-sectional view (a) shows the cross-sectional structure between P-Q in the top view (b). Figure 13(c) is an enlarged top view of the convex portion 19, and Figure 13(d) is an enlarged cross-sectional view of the convex portion 19.

[0121] In this example, the convex portion 19 is a quadrangular prism, the surface opening of the closed recess 20 is circular, and the bottom surface 20a of the closed recess 20 is a part of a spherical surface with a curvature r.

[0122] Ninth Embodiment FIG. 14 is a structural explanatory view of a stamp component for transferring a minute structure according to a ninth embodiment of the present invention.

[0123] Figure 14(a) is a top view of the convex portion 19, Figure 14(b) is a cross-sectional view of the T-U plane of Figure 14(a), and Figure 14(c) is a cross-sectional view of the V-W plane of Figure 14(a). The silicone rubber film and substrate are not shown, and only the convex portion 19 formed on the surface of the silicone rubber film is depicted. In Figure 14, 21 is a closed recess formed on the surface 19a of the convex portion 19.

[0124] As shown in Figure 14(a), the basic shape of the surface opening of the closed recess 21 is a square, and the four vertices of the square are part of an arc with a radius of curvature r0. For example, it is recommended to use 1 / 4 of an arc with a radius of r0. This allows the tangents between the arc and the sides of the rectangle to be the same, thereby reducing deformation distortion when the bottom surface 21a of the recess is temporarily bonded to the microstructure without any gaps.

[0125] As shown in Figures 14(b) and (c), by varying the radius of curvature of the bottom surface 21a of the closed recess 21 in the direction perpendicular to the sides of the rectangle (TU) and the diagonal direction of the rectangle (V-W), and forming the closed recess 21 at the same depth at the center point, deformation of the closed recess 21 can be minimized when the recess bottom surface 21a is temporarily bonded to the microstructure without gaps. In this case, it is of course advisable to design and form the bottom surface 21a of the recess 21 smoothly by optimizing the intermediate value of the two radii of curvature r1 and r2 depending on the rotation angle direction between the (TU) and (V-W) directions. In this way, by utilizing an aspherical recess bottom structure, the temporary adhesive strength between the microstructure surface plane and the closed recess 21 on the convex portion surface 19a can be maximized.

[0126] 10th Embodiment Fig. 15 is a structural explanatory diagram of a stamp component 100 for transferring a microstructure according to a 10th embodiment of the present invention. In Fig. 15, 22 denotes a convex portion formed on the surface 2a of the silicone rubber film 2, and 23 denotes a closed recess formed on the surface 22a of the convex portion.

[0127] FIG. 15(a) is a cross-sectional view of this embodiment, and FIG. 15(b) is a top view of this embodiment. The cross-sectional view (a) shows the cross-sectional structure between P-Q in the top view (b). FIG. 15(c) is an enlarged top view of the convex portion 22, and FIG. 15(d) is an enlarged cross-sectional view of the convex portion 22. In this embodiment, a large number of convex portions 22 are formed in a matrix. Furthermore, in this embodiment, the convex portion 22 is cylindrical, and a recessed bottom shape consisting of a portion of a sphere with a curvature radius r is formed on its surface. Thus, if the surface shape of the convex portion 22 is circular, i.e., if the convex portion 22 is a cut-out portion of a cylinder or a conical cylinder, deformation strain of the closed recess 23 can be reduced when the microstructure and the recessed bottom 23a are temporarily bonded without gaps. In other words, after temporary bonding, the shape restoration force of the closed recess 23 can be uniform, allowing for stable temporary bonding. The same effect can be obtained even if the surface shape of the convex portion 22 is elliptical.

[0128] Although the above description takes as an example a case where the shape of the recess bottom surface 23a is a portion of a sphere with a radius of curvature r, the shape of the bottom surface may also be aspherical in the radial direction. For example, the recess bottom surface 23a may include a parabolic surface. More precisely, the shape can be designed by incorporating the physical properties of the silicone-based rubber film used through simulation, and then optimally achieving the ease of deformation during temporary bonding and the optimal restoring force after temporary bonding, i.e., the optimal temporary adhesive force (the adhesive force + tackiness + suction force of the silicone-based rubber film).

[0129] 11th Embodiment Fig. 16(a) is a structural explanatory diagram of a stamp part 100 for transferring a microstructure according to an 11th embodiment of the present invention. In this embodiment, the basic structure of the stamp part is the same as that of the 10th embodiment of the present invention. The difference is that, as shown in the top view of Fig. 16(a), the convex parts 22 are arranged in a matrix at a fixed pitch (Xp, Yp) required by the placement location on the receiving substrate side.

[0130] By arranging and configuring the convex portions that grip the microstructures in a matrix at a desired pitch, the device is suitable for electronic device assembly and 3D packaging, where electrical and electronic components are arranged at a fixed pitch. It is also extremely useful for the transfer and assembly of micro LEDs, which require arranging LEDs at a desired display pitch.

[0131] 16(b) and (c) are explanatory diagrams showing the operation of the stamp part 100 for transferring a minute structure according to the eleventh embodiment of the present invention. Figures 16(d) and (e) are enlarged cross-sectional views of different parts of Figure 16(c).

[0132] 16(b) to 16(e), 24 is a supply substrate for the microstructure, and 25 and 26 are microstructures. The difference between the microstructure 25 and the microstructure 26 is their size, with the microstructure 25 being smaller than the area of ​​the convex portion of the convex portion 22, and the microstructure 26 being larger than the area of ​​the convex portion 22.

[0133] Figure 16(b) shows a state in which the microstructures are arranged in the desired matrix on the supply substrate 24 side, just like on the convex portion 22. Figure 16(c) shows a state in which the microstructure transfer stamp 100 of this embodiment is pressed against the supply substrate 24, and the microstructures 25 and 26 are grasped from the supply substrate 24. Furthermore, Figure 16(d) is an enlarged view of the grasped microstructure 25, showing the state in which the microstructure 25 is temporarily adhered to the bottom surface of the closed recess 23. Figure 16(e) is an enlarged view of the grasped microstructure 26, showing the state in which the microstructure 26 is temporarily adhered to the bottom surface of the closed recess 23.

[0134] As shown in Figure 16(d), when the microstructure 25 is smaller than the convex portion 22, it is temporarily adhered so as to wrap around the periphery of the microstructure 25 in an overhanging manner. On the other hand, as shown in Figure 16(e), when the microstructure 26 is larger than the convex portion 22, the entire bottom surface of the recess is adhered to the temporary adhesion surface of the microstructure 26. In either case, it is adhered so as to eliminate the space of the closed recess 23 that existed before the convex portion 22 was grasped, and it can be temporarily adhered to the microstructures 25 and 26 like a so-called suction cup.

[0135] In the first embodiment (Figure 1) to the seventh embodiment (Figure 12), the cavity in the completely closed recess did not disappear after the microstructure was temporarily bonded, but by designing the recess as in the eighth embodiment (Figure 13) to the eleventh embodiment (Figure 16) of the present invention, no cavity occurs between the bottom of the recess and the bonding surface of the microstructure.

[0136] 17 shows structural explanatory diagrams of several examples of stamp components 100 for transferring a microstructure according to a twelfth embodiment of the present invention. In particular, cross-sectional views of the convex portion 12 in a plane direction perpendicular to the substrate 1, i.e., in the height direction, are shown.

[0137] 17, 27, 28, and 30 denote parts of the convex portion 12, and 29 denotes a closed recess. 27 denotes a first-stage convex-shaped protrusion, 28 denotes a second-stage convex-shaped protrusion, and 30 denotes a third-stage convex-shaped protrusion.

[0138] Fig. 17(a) shows a configuration in which the convex portion 12, which is a cylinder or polygonal prism, is configured in two stages, consisting of convex-shaped protrusions 27 and 28. Fig. 17(b) shows a configuration in which the first-stage convex-shaped protrusion 27 is a cylinder or polygonal prism, and the second-stage convex-shaped protrusion 28, which is a circular or polygonal frustum, is formed on top of it. Fig. 17(c) shows a state in which both of the two-stage convex-shaped protrusions 27 and 28 are configured as circular or polygonal frustum. In this way, configuring the convex portion 12 with multiple convex-shaped protrusions is an effective means for improving the reduction in mechanical strength that occurs when the convex portion 12 is miniaturized.

[0139] 17(d) and (e) show a state in which the convex portion 12 is configured by three-tiered convex-shaped protrusions 27, 28, and 30 of a circular or polygonal frustum. In Fig. 17(d), the cross-sectional shape (profile) of the convex portion 12 in the height direction shows a shape that is convex on the inside of the convex portion 12. In Fig. 17(e), the cross-sectional shape (profile) of the convex portion 12 in the height direction shows a shape that is convex on the outside of the convex portion 12.

[0140] 17(d) is useful when the convex portion 12 is relatively large and needs to be transferred without interfering with adjacent microstructures that are densely arranged, and is also useful when the distance between the convex portion 12 and the adjacent convex portion 12 is short. On the other hand, the case of Fig. 17(e) is effective in preventing a decrease in the mechanical strength of the convex portion 12 when the convex portion 12 is smaller than several hundred µm.

[0141] In this way, the degree of freedom in design can be greatly expanded by configuring the convex portion 12 in multiple stages by combining a cylinder, a polygonal prism, a truncated cone, and a truncated polygonal pyramid. For even more advanced design, by utilizing simulation, it is possible to design a smoother profile shape beyond the multiple stage combination.

[0142] Although FIG. 17 shows a closed recess 29 with a spherical bottom surface, the effect of the cross-sectional profile of the convex portion 12 is exerted regardless of the shape of the closed recess 29 .

[0143] In the twelfth embodiment, as shown in FIG. 17, the surface of the uppermost projection 28 or 30 of the two or more stages of convex-shaped projections has a closed recess 29 .

[0144] Thirteenth Embodiment FIG. 18 shows structural explanatory diagrams of several examples of stamp components 100 for transferring a minute structure according to a thirteenth embodiment of the present invention.

[0145] In Fig. 18, 31 denotes a conductive film formed between the substrate 1 and the silicone rubber film 2. Figs. 18(a), (c), and (e) show cases where the silicone rubber film 2 does not have a convex portion, while Figs. 18(b), (d), and (f) show cases where the silicone rubber film 2 has at least one convex portion 12. Although not shown, the surfaces 2a of the silicone rubber films 2 in Figs. 18(a), (c), and (e), and the surfaces 12a of the convex portions 12 in Figs. 18(b), (d), and (f) have closed recesses.

[0146] Figures 18(a) and (b) show cases where a silicone rubber film 2 is formed in an area smaller than the substrate 1, and a conductive film 31 is formed in the same area as the silicone rubber film 2. Figures 18(c) and (d) show cases where the conductive rubber film 31 is formed over the entire surface of one surface of the substrate 1. Of course, the conductive film 31 may not be formed over the entire surface of one surface of the substrate 1, but may be formed over an area larger than the area of ​​the silicone rubber film 2. Figures 18(e) and (f) show cases where the silicone rubber film 2 and the conductive film 31 are both formed over the entire surface of one surface of the substrate 1.

[0147] While this problem can be adequately solved by controlling the installation environment and internal environment of the transfer machine that performs the transfer operation using the stamp component of the present invention, it is extremely difficult to completely eliminate the risk of floating particles due to static electricity adhering to the stamp component and degrading the temporary adhesion of the stamp component to the microstructure. Forming the conductive film of this embodiment between the substrate and the silicone rubber film is extremely effective as a way to further mitigate this problem and increase the operating time of the transfer device. This configuration significantly reduces the adhesion of particles to the adhesive surface due to static electricity.

[0148] Therefore, it is possible to simultaneously achieve two effects: the ability to adjust the adhesive strength of the silicone rubber film by designing the closed recesses, and particle suppression.

[0149] Fourteenth Embodiment FIG. 19 shows structural explanatory diagrams of several examples of a stamp component 100 for transferring a minute structure according to a fourteenth embodiment of the present invention.

[0150] In Figure 19, 32 is a conductive silicone rubber film, and 33 to 36 are convex portions, showing various variations. Although not shown, the surface 32a of the silicone rubber film 32 in Figure 19(a) and the surfaces 33a, 34a, 35a, and 36a of the convex portions 33 to 36 in Figures 19(b) to 19(f) have closed recesses.

[0151] In the convex portions 34 and 35 of FIGS. 19(d) and 19(e), the cross section of the final convex projection is in the shape of a truncated cone.

[0152] The greatest feature of this embodiment is that the silicone rubber film 32 itself is a conductive film. To impart conductivity to the silicone rubber film, a carbon-based conductive film such as carbon, carbon nanofiber, graphite, or graphene is mixed in as a filler.

[0153] Although Figure 19 shows a state in which the conductive silicone rubber film 32 is formed in a limited area on the substrate 1, the conductive silicone rubber film 32 may be formed over the entire surface of the substrate 1.

[0154] By configuring in this way, it is possible to prevent particles generated during the transfer operation from adhering to the stamp component.

[0155] In the stamp parts for transferring microstructures described above in the embodiments of the present invention, the surface opening shape of the closed recess may be any closed shape, such as a circle, an ellipse, a ring, or a polygon such as a triangle, a rectangle (square, oblong), a quadrangle, a pentagon, and a hexagon.

[0156] It is most convenient for processing if the surface shape of the substrate and the surface shape of the silicone rubber film are square or rectangular, but any shape may be used, including circle, ellipse, and polygons such as triangle, square, and hexagon.

[0157] The following describes the formation of the silicone rubber film described above. A flat silicone rubber film with a closed recess and a silicone rubber film with a convex portion and a closed recess on its surface can be formed by, for example, an imprinting method. The curing reaction of the silicone rubber film may be thermal curing or UV curing.

[0158] It should be noted that methods other than the imprint method are not limited to injection molding, and any method may be used as long as it can form the structure of the present invention.

[0159] In the stamp component for transferring a minute structure of the present invention, a quartz substrate can be used as the substrate. When a synthetic quartz substrate is used as the quartz substrate, performance is dramatically improved.

[0160] Synthetic quartz substrates can achieve a total thickness variation (TTV) of approximately 1 μm or less, significantly improving the in-plane height uniformity of stamp components compared to general quartz substrates. That is, when transferring multiple microstructures at once, stamp components can be pressed more uniformly on both the supply substrate and the receiving substrate. More specifically, the timing at which the surfaces of the convex portions formed on the surface of the silicone-based rubber film or silicone-based rubber film contact the microstructures becomes more uniform, resulting in a more uniform indentation depth. Therefore, using a stamp component using a synthetic quartz substrate ensures a consistent temporary adhesive strength for all multiple microstructures, enabling stable microstructure transfer. Needless to say, this effect can also be achieved when transferring a single microstructure using a convex portion formed on the surface of the silicone-based rubber film or silicone-based rubber film.

[0161] Another benefit of using synthetic quartz glass is its thermal stability. Synthetic quartz glass substrates have a thermal expansion coefficient that is approximately one-fifth that of other quartz glass substrates, reducing thermal distortion during operation. This is particularly useful for stamp components with convex protrusions, as it reduces displacement and distortion of the protrusions due to thermal expansion and contraction, making it ideal for repeated transfer operations.

[0162] Furthermore, using a sapphire substrate instead of a quartz substrate provides a stamp component for transferring microstructures that is superior in durability because it has higher mechanical strength than a quartz (including synthetic quartz) substrate. The in-plane uniformity of the sapphire substrate surface is 15 microns or less in total thickness variation (TTV), making it suitable for use as a substitute for a quartz substrate.

[0163] Furthermore, if a silicon wafer or a silicon wafer piece is used instead of the quartz substrate, it is possible to provide a stamp component for transferring a minute structure that is even more excellent in flatness than a synthetic quartz substrate.

[0164] If the size of the microstructure to be transferred is larger than several hundred micrometers and flatness is acceptable, a glass substrate may be used instead of the quartz substrate.

[0165] For example, the silicone rubber film may be made of PDMS (polydimethylsiloxane), a silicone composition in which the side chains and both ends of PDMS have been modified, or a composition consisting of a combination thereof. By adjusting the composition of each material (molecular weight, modifying group, modifying substance, modification amount, etc.) and, in the case of a mixture, the mixing ratio, etc., physical properties such as material hardness, pressure-sensitive adhesive strength, and repeated adhesion can be controlled. In addition to mixing, various modified silicone compositions can also be optimized by crosslinking or three-dimensionally structuring the molecules.

[0166] In addition, examples of objects that can be transferred using the stamp part for transferring microstructures of the present invention include semiconductor chips and various electrical (resistors, coils, capacitors, etc.) and electronic elements (diodes, transistors, thyristors, various high-performance LSI / IC chips, 3D mounted chips, SAW filter elements, MEMS chips such as acceleration sensors, and even LEDs, particularly mini LEDs and micro LEDs, etc.), and the present invention is applicable to the mounting of these and the assembly of electrical and electronic devices, etc.

[0167] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A stamp part for transferring microstructures, characterized in that a silicone rubber film is formed on a substrate, and the surface of the silicone rubber film opposite the substrate has one or more recesses that are closed except for the surface opening.

2. The stamp component for transferring a minute structure according to claim 1, characterized in that the shape of the surface opening of the closed recess is selected from the group consisting of a circle, an ellipse, a ring, and a polygon.

3. A stamp component for transferring a minute structure according to claim 1 or 2, characterized in that the depth of said closed recess does not reach said substrate.

4. A stamp part for transferring a microstructure as described in any one of claims 1 to 3, characterized in that a plurality of the closed recesses are arranged in a matrix on the surface of the silicone rubber film.

5. A stamp part for transferring a microstructure as described in any one of claims 1 to 3, characterized in that a plurality of the closed recesses are arranged in a geometric pattern on the surface of the silicone rubber film.

6. A stamp component for transferring a minute structure according to any one of claims 1 to 5, characterized in that the portions of the surface of the silicone rubber film other than the closed recesses have a lattice pattern.

7. A stamp part for transferring a minute structure according to any one of claims 1 to 5, characterized in that the portion of the surface of the silicone rubber film other than the closed recesses has a cross-sectional pattern of a honeycomb structure.

8. The stamp component for transferring a minute structure according to claim 1, wherein the closed recesses on the surface of the silicone rubber film include at least an annular recess.

9. A stamp part for transferring a microstructure as described in claim 1, characterized in that the closed recesses include a first closed recess and a second closed recess having different surface opening areas, and the surface opening area of ​​the second closed recess is smaller than the surface opening area of ​​the first closed recess.

10. A stamp part for transferring microstructures, characterized in that a silicone rubber film is formed on a substrate, one or more convex portions are formed on the surface of the silicone rubber film opposite the substrate, and the surface of the convex portion has one or more concave portions that are closed except for the surface opening.

11. A stamp part for transferring a microstructure as described in claim 10, characterized in that the convex portion includes a convex-shaped protrusion of two or more steps, and the uppermost surface of the convex-shaped protrusion of two or more steps has one or more closed recesses.

12. A stamp component for transferring a minute structure according to claim 10 or 11, characterized in that the closed recess has a bottom surface with a curve.

13. The stamp component for transferring a minute structure according to claim 12, wherein the bottom surface of the closed recess is a spherical surface or an aspherical surface.

14. A stamp component for transferring a minute structure according to any one of claims 10 to 13, characterized in that the surface opening of the closed recess has a circular or elliptical shape.

15. A stamp component for transferring a minute structure according to any one of claims 10 to 13, characterized in that the surface opening of the closed recess is polygonal, and the vertices of the polygon are arc-shaped.

16. A stamp component for transferring a microstructure according to any one of claims 10 to 15, characterized in that a plurality of the convex portions are formed on the surface of the silicone rubber film, and the plurality of convex portions are arranged in a matrix at a constant pitch in the X and Y directions.

17. A stamp component for transferring a minute structure according to any one of claims 10 to 16, characterized in that the convex portion is cylindrical, polygonal prism-shaped, frustum-shaped, or a multi-step shape that is a combination of these.

18. A stamp component for transferring a minute structure according to any one of claims 10 to 17, characterized in that the cross-sectional shape of the convex portion in the height direction is a shape that convex toward the inside of the convex portion.

19. A stamp component for transferring a minute structure according to any one of claims 10 to 17, characterized in that the cross-sectional shape of the convex portion in the height direction is a shape that is convex outward from the convex portion.

20. A stamp component for transferring a minute structure according to any one of claims 1 to 19, characterized in that a conductive film is formed between the substrate and the silicone rubber film.

21. A stamp component for transferring a minute structure according to any one of claims 1 to 19, characterized in that the silicone rubber film is a conductive film.

22. A stamp part for transferring a minute structure according to any one of claims 1 to 21, characterized in that the substrate is a quartz substrate.

23. A stamp part for transferring a minute structure according to claim 22, wherein the quartz substrate is a synthetic quartz substrate.

24. A stamp part for transferring a minute structure according to any one of claims 1 to 21, characterized in that the substrate is a sapphire substrate.

25. A stamp part for transferring a minute structure according to any one of claims 1 to 21, characterized in that the substrate is a silicon wafer or a silicon wafer fragment.