Methods to prevent grain transfer that encapsulates air bubbles

Abstract

This invention provides a method for preventing crystal transfer that traps air bubbles, comprising the following steps: an adsorption device adsorbs crystals by a first negative pressure, causing the crystals to bend; a crystal-fixing device blows a crystal placement area by a positive pressure, causing the crystal placement area to bulge upwards, with the center of the crystal placement area contacting the center of the crystal, forming a gap between the periphery of the crystal placement area and the periphery of the crystal; the adsorption device stops adsorbing crystals by the first negative pressure, the crystal returns to a flat state and detaches from the adsorption device, the crystal-fixing device stops blowing the crystal placement area by positive pressure, and the crystal placement area returns to a flat state; the crystal and the crystal placement area squeeze the air in the gap outwards, causing the gap to close, and the bottom surface of the crystal tightly adheres to the top surface of the crystal placement area. Therefore, this invention can achieve the effect of preventing crystals and the crystal placement area from trapping air bubbles.

Description

Technical Field

[0001] This invention relates to a grain transfer method, and more particularly to a grain transfer method that prevents air bubbles from being trapped. Background Technology

[0002] Integrated circuits are fabricated on semiconductor wafers through mass production and multiple processes. The wafers are then further divided into numerous individual chips. In other words, a chip is a small, unpackaged piece of integrated circuit material made from semiconductor material.

[0003] Figure 1 This is a schematic diagram of step S10 in a conventional grain transfer method. Figure 2 This is a schematic diagram of step S20 in a conventional grain transfer method. Figure 3 This is a schematic diagram of step S30 in a conventional grain transfer method. Step S10, as follows: Figure 1 As shown, a plurality of segmented crystal grains 120 are neatly attached to a carrier film 110. An outer pushing member 141 of a pushing device 140 abuts against the bottom surface of the carrier film 110, and an inner pushing member 142 of the pushing device 140 pushes a target block 111 of the carrier film 110, causing the target block 111 to bulge upwards, and the crystal grains 20 on the target block 111 contact a suction nozzle 132 of an adsorption device 130. Step S20, as follows Figure 2 As shown, a vacuum device (not shown) evacuates air from a first vacuum channel (not shown) of a fixed base 131 of the adsorption device 130. Gas in a groove 1322 of the suction nozzle 132 sequentially passes through a second vacuum channel 1321 of the suction nozzle 132 and the first vacuum channel of the fixed base 131 to generate a vacuum and provide a first negative pressure 161. The first negative pressure 161 adsorbs the crystal grains 20 through the groove 1322. Step S30, as... Figure 3 As shown, the vacuum device stops pumping air into the first vacuum channel, and the first vacuum channel, the second vacuum channel 1321 and the groove 1322 no longer generate a vacuum. The vacuum device no longer provides the first negative pressure 161, so the suction nozzle 132 stops adsorbing the crystal 120 by the first negative pressure 161. Finally, the crystal 120 is placed on a crystal placement area 151 of a thin film 150.

[0004] However, as Figure 2 As shown, when the suction nozzle 132 adsorbs larger grains 120 (greater than 5×5 mm) or thin grains 120 (less than 200 μm), the adsorption area of ​​the first negative pressure 161 is quite large because the area of ​​the groove 1322 is also quite large. When the first negative pressure 161 adsorbs the grains 120 through the groove 1322, the grains 120 will bend inward and sink into the groove 1322. Therefore, as... Figure 3As shown, after the die 120 is placed in the die placement area 151, the bottom surface of the curved die 120 and the top surface of the flat die placement area 151 will together enclose the air bubble and form a void 91. This causes the die 120 and the die placement area 151 to not fit completely tightly, making the subsequent processing of picking or identifying the die 120 easily affected by the air bubble, thus reducing the yield of the products produced by the subsequent processing.

[0005] Figure 4 A schematic diagram is shown of a conventional all-planar suction nozzle 132A adsorbing a flat-surfaced grain 120. The conventional all-planar suction nozzle 132A has only a second vacuum channel 1321 and no groove 1322, therefore its bottom surface is quite flat. Thus, the conventional all-planar suction nozzle 132A can adsorb the grain 120 through the second vacuum through-hole 1321 by means of a first negative pressure 161. Because the aperture of the second vacuum through-hole 1321 is quite small, the adsorption area of ​​the first negative pressure 161 is quite small. When the first negative pressure 161 adsorbs the grain 120 through the second vacuum through-hole 1321, the grain 120 will not bend inwards, thus the grain 120 can remain flat. After the die 120 is placed in the die placement area 151, the flat bottom surface of the die 120 and the flat top surface of the die placement area 151 are completely and tightly attached, and will not jointly enclose the air bubble. Therefore, no void 91 is formed. As a result, the subsequent processing of picking or identifying the die 120 will not be affected by the air bubble, thus improving the yield of the products produced by subsequent processing.

[0006] Figure 5 A schematic diagram is shown of a conventional all-planar nozzle 132A adsorbing a grain 120A with an uneven surface. In some cases, the surface of the grain 120A is uneven, for example, due to the adhesion of microparticles to the surface of the grain 120A, or the presence of copper bumps or pads on the grain 120A, resulting in a gap 190 between the top surface of the grain 120A and the bottom surface of the conventional all-planar nozzle 132A. Because the gap 190 connects the second vacuum channel 1321 and the external space, the second vacuum channel 1321 cannot generate a vacuum, so the conventional all-planar nozzle 132A is completely unable to adsorb the grain 120A using the first negative pressure 161. Summary of the Invention

[0007] This invention provides a method for preventing bubble encapsulation during grain transfer, which can completely squeeze out the air in the gap between the grain and the grain placement area, thus completely eliminating the situation where the grain and the grain placement area encapsulate bubbles and achieving the effect of preventing bubble encapsulation.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A method for preventing the transfer of crystals encapsulated by air bubbles includes the following steps: (a) an adsorption device adsorbs a crystal by a first negative pressure and moves it above a crystal placement area of ​​a thin film, the crystal bending inward; (b) a crystal bonding device blows the crystal placement area with a positive pressure, causing the crystal placement area to bulge upward, and the center of the crystal placement area contacts the center of the crystal, forming a gap between the periphery of the crystal placement area and the periphery of the crystal; and (c) the adsorption device stops adsorbing the crystal by the first negative pressure, causing the crystal to return to a flat state and detach from the adsorption device, while the crystal bonding device stops blowing the crystal placement area with positive pressure, causing the crystal placement area to return to a flat state; during the process of the crystal and the crystal placement area returning to a flat state simultaneously, the crystal and the crystal placement area together gradually squeeze the air in the gap outward, causing the gap to close; after the gap is completely closed, the bottom surface of the crystal is tightly attached to the top surface of the crystal placement area.

[0010] In some embodiments, in step (b), the curvature of the grain placement region is greater than the curvature of the grain.

[0011] In some embodiments, in step (b), under the condition of positive pressure average, the stress balance of the positive pressure blowing grain placement area is achieved, causing the grain placement area to bulge upward.

[0012] In some embodiments, in step (b), the pressure of the positive pressure is greater closer to the axis of the die bonding device, so that the degree of bulging of the grain placement area gradually increases from the periphery of the grain placement area toward the center.

[0013] In some embodiments, the adsorption device includes a fixed base and a suction nozzle. The fixed base has a first vacuum channel connected to a vacuum device. The suction nozzle is disposed at the bottom of the fixed base and has a second vacuum channel and a groove. The second vacuum channel communicates with the first vacuum channel, and the groove communicates with the second vacuum channel. In step (a), the vacuum device evacuates the first vacuum channel, and the gas in the groove passes through the second vacuum channel and the first vacuum channel in sequence to generate a vacuum and provide a first negative pressure. The first negative pressure adsorbs the crystal grains through the groove, causing the crystal grains to bend inward and sink into the groove. In step (c), the vacuum device stops evacuating the first vacuum channel, and the first vacuum channel, the second vacuum channel, and the groove no longer generate a vacuum. The vacuum device no longer provides the first negative pressure, and therefore the suction nozzle stops adsorbing the crystal grains by means of the first negative pressure.

[0014] In some embodiments, the die bonding apparatus has a first pressure channel located in the middle of the die bonding apparatus and connected to a gas supply device; wherein, in step (b), the gas supply device supplies gas to the first pressure channel to generate an airflow and provide positive pressure, the positive pressure blowing the grain placement area through the first pressure channel; and wherein, in step (c), the gas supply device stops supplying gas to the first pressure channel, the first pressure channel no longer generates an airflow, the gas supply device no longer provides positive pressure, and thus the die bonding apparatus stops blowing the grain placement area by positive pressure.

[0015] In some embodiments, an annular body divides the first air pressure channel into a first chamber and a second chamber, and a through hole is formed in the middle of the annular body, which connects the first chamber and the second chamber, and the diameter of the through hole is smaller than the diameter of the first chamber and the second chamber.

[0016] In some embodiments, the width of the first pressure channel is equal to the width of the grain placement region.

[0017] In some embodiments, in step (b), the die-bonding device adsorbs the outside of the die placement area by a second negative pressure, and the adsorption device moves toward the die placement area; and in step (c), the adsorption device is moved away from the die, while the die-bonding device stops adsorbing the outside of the die placement area by the second negative pressure.

[0018] In some embodiments, the die bonding apparatus has a plurality of second pressure channels, which are spaced apart along a circumferential direction and connected to a vacuum device; wherein, in step (b), the vacuum device evacuates the plurality of second pressure channels to generate a vacuum and provides a second negative pressure, which adsorbs the outer side of the grain placement area through the plurality of second pressure channels; and wherein, in step (c), the vacuum device stops evacuating the plurality of second pressure channels, the plurality of second pressure channels no longer generate a vacuum, the vacuum device no longer provides a second negative pressure, and thus the die bonding apparatus stops adsorbing the outer side of the grain placement area by means of the second negative pressure.

[0019] The beneficial effects of this invention are:

[0020] The method of this invention can completely squeeze out the air in the gap between the grain and the grain placement area, completely eliminating the possibility of air bubbles being trapped between the grain and the grain placement area, thus achieving the effect of preventing air bubble trapping. As a result, there will be no voids between the grain and the grain placement area, and subsequent processing procedures for picking or identifying grains will not be affected by air bubbles, improving the yield of products manufactured through subsequent processing. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of step S10 in a conventional grain transfer method.

[0022] Figure 2 This is a schematic diagram of step S20 in a conventional grain transfer method.

[0023] Figure 3 This is a schematic diagram of step S30 in a conventional grain transfer method.

[0024] Figure 4 This diagram shows a conventional all-planar nozzle adsorbing grains with a flat surface.

[0025] Figure 5 This diagram shows a conventional all-planar nozzle adsorbing grains with an uneven surface.

[0026] Figure 6 This is a flowchart of a method according to an embodiment of the present invention.

[0027] Figure 7 This is a schematic diagram of step S100 of the method according to an embodiment of the present invention.

[0028] Figure 8A This is a perspective view of step S200 of the method according to an embodiment of the present invention.

[0029] Figure 8B This is a schematic diagram of step S200 of the method according to an embodiment of the present invention.

[0030] Figure 8C This is a schematic diagram of the adsorption device and vacuum device according to an embodiment of the present invention.

[0031] Figure 9A This is a perspective view of step S300 of the method according to an embodiment of the present invention.

[0032] Figure 9B This is a schematic diagram of step S300 of the method according to an embodiment of the present invention.

[0033] Figure 9C This is a schematic diagram of the die bonding device, vacuum device, and gas supply device according to an embodiment of the present invention.

[0034] Figure 10A This is a perspective view of step S400 of the method according to an embodiment of the present invention.

[0035] Figure 10B This is a schematic diagram of step S400 of the method according to an embodiment of the present invention.

[0036] Figure 11A This is a top view of a preferred embodiment of the adsorption device of the present invention.

[0037] Figure 11B This is a top view of another embodiment of the adsorption device of the present invention.

[0038] Figure 12A This is a top view of a preferred embodiment of the die bonding apparatus of the present invention.

[0039] Figure 12B This is a top view of another embodiment of the die bonding apparatus of the present invention.

[0040] Figures 13A to 13C This is a schematic diagram of another embodiment of step S300 of the method of this invention.

[0041] Figure 14 to Figure 14B This is a schematic diagram of another embodiment of step S300 of the method of this invention.

[0042] Explanation of symbols in the attached drawings:

[0043] 10,110: Supporting membrane;

[0044] 11,111: Target block;

[0045] 20, 120, 120A: Grain size;

[0046] 30,30A,130: Adsorption device;

[0047] 31, 31A, 131: Fixture;

[0048] 311: First vacuum channel;

[0049] 32, 32A, 132, 132A: Suction nozzle;

[0050] 321, 1321: Second vacuum channel;

[0051] 322, 322A, 1322: Groove;

[0052] 40,140: Pricing device;

[0053] 41,141: External pusher component;

[0054] 42,142: Inner pusher component;

[0055] 50,150: film;

[0056] 51,151: Grain placement area;

[0057] 60: Vacuum device;

[0058] 61,161: First negative pressure;

[0059] 62: Second negative pressure;

[0060] 70, 70A: Die bonding device;

[0061] 71, 71A: First pressure channel;

[0062] 711: First chamber;

[0063] 712: Second chamber;

[0064] 72: Second air pressure channel;

[0065] 73: Ring body;

[0066] 731: Through hole;

[0067] 80: Gas supply device;

[0068] 81: Positive pressure;

[0069] 90,190: Gap;

[0070] 91: Hollow;

[0071] S10~30: Steps;

[0072] S100~400: Steps. Detailed Implementation

[0073] To make the technical problems, technical solutions, and advantages of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments. In the following description, specific details such as particular configurations and components are provided merely to aid in a comprehensive understanding of the embodiments of this invention. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this invention. Furthermore, for clarity and brevity, descriptions of known functions and structures have been omitted.

[0074] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0075] This invention provides a method for preventing grain transfer that encapsulates air bubbles, comprising the following steps:

[0076] Step S100, as follows Figure 6 and Figure 7As shown, a grain 20 on a carrier film 10 comes into contact with an adsorption device 30. More specifically, an outer pushing member 41 of a pushing device 40 abuts against the bottom surface of the carrier film 10, and an inner pushing member 42 of the pushing device 40 pushes a target block 11 of the carrier film 10, causing the target block 11 to bulge upward, and the grain 20 on the target block 11 comes into contact with the adsorption device 30.

[0077] Step S200, as follows Figure 6 , Figure 8A , Figure 8B and Figure 8C As shown, the adsorption device 30 adsorbs the crystal grains 20 by a first negative pressure 61 and moves them above a crystal grain placement area 51 of a thin film 50, causing the crystal grains 20 to bend inward. More specifically, the adsorption device 30 includes a fixed base 31 and a suction nozzle 32. The fixed base 31 has a first vacuum channel 311 connected to a vacuum device 60. The suction nozzle 32 is located at the bottom of the fixed base 31 and has a second vacuum channel 321 and a groove 322. The second vacuum channel 321 communicates with the first vacuum channel 311, and the groove 322 communicates with the second vacuum channel 321. The vacuum device 60 evacuates the first vacuum channel 311, and the gas in the groove 322 passes sequentially through the second vacuum channel 321 and the first vacuum channel 311 to generate a vacuum and provide the first negative pressure 61. The first negative pressure 61 adsorbs the crystal grains 20 through the groove 322, causing the crystal grains 20 to bend inward and sink into the groove 322.

[0078] Step S300, as follows Figure 6 , Figure 9A , Figure 9B and Figure 9CAs shown, a die-bonding device 70 uses a second negative pressure 62 to adsorb the outer side of the grain placement area 51. The adsorption device 30 moves towards the grain placement area 51, while the die-bonding device 70 uses a positive pressure 81 to blow the grain placement area 51, causing the grain placement area 51 to bulge upwards, and the center of the grain placement area 51 to contact the center of the grain 20. A gap 90 is formed between the periphery of the grain placement area 51 and the periphery of the grain 20. More specifically, the die-bonding device 70 has a first air pressure channel 71 and a plurality of second air pressure channels 72. The first air pressure channel 71 is located in the middle of the die-bonding device 70 and is connected to a gas supply device 80. The plurality of second air pressure channels 72 are arranged at intervals around the outer side of the first air pressure channel 71 along a circumferential direction and are connected to a vacuum device 60. Vacuum device 60 evacuates the plurality of second pressure channels 72 to create a vacuum and provides a second negative pressure 62, which adsorbs the outer side of the grain placement area 51 through the plurality of second pressure channels 72. Gas supply device 80 supplies gas to the first pressure channel 71 to create an airflow and provides a positive pressure 81, which blows through the first pressure channel 71 onto the grain placement area 51.

[0079] Step 400, such as Figure 6 , Figure 10A and Figure 10BAs shown, the adsorption device 30 stops adsorbing the crystal grain 20 by the first negative pressure 61, so that the crystal grain 20 returns to a flat state and detaches from the adsorption device 30. At the same time, the crystal fixing device 70 stops blowing the crystal grain placement area 51 by the positive pressure 81, so that the crystal grain placement area 51 returns to a flat state. During the process of the crystal grain 20 and the crystal grain placement area 51 returning to a flat state simultaneously, the crystal grain 20 and the crystal grain placement area 51 together gradually squeeze the air in the gap 90 outward, so that the gap 90 gradually closes. After the gap 90 is completely closed, the bottom surface of the crystal grain 20 is tightly attached to the top surface of the crystal grain placement area 51. More specifically, the vacuum device 60 stops evacuating the first vacuum channel 311, so the first vacuum channel 311, the second vacuum channel 321, and the groove 322 no longer generate vacuum. The vacuum device 60 no longer provides the first negative pressure 61, and therefore the suction nozzle 32 stops adsorbing the crystal 20 by means of the first negative pressure 61. The gas supply device 80 stops supplying gas to the first pressure channel 71, so the first pressure channel 71 no longer generates airflow. The gas supply device 80 no longer provides the positive pressure 81, and therefore the die-bonding device 70 stops blowing the crystal placement area 51 by means of the positive pressure 81. Because the crystal 20 is no longer adsorbed by the first negative pressure 61, the crystal 20 will gradually extend from its center to its periphery, and eventually the crystal 20 will automatically return to a flat state. Because the crystal placement area 51 is no longer blown by the positive pressure 81, the crystal placement area 51 will gradually extend from its center to its periphery, and eventually the crystal placement area 51 will automatically return to a flat state. During the process of the grain 20 and the grain placement area 51 synchronously restoring to a flat state, because both the grain 20 and the grain placement area 51 extend synchronously from the center outwards, a bonding wave (not shown) is formed between the grain 20 and the grain placement area 51. The bonding wave gradually diffuses from the center of the grain 20 outwards, so the grain 20 and the grain placement area 51 can jointly squeeze the air in the gap 90 outwards from the center of the gap 90 outwards, causing the gap 90 to gradually close from the center outwards. After the gap 90 is completely closed, the bottom surface of the grain 20 can be completely and tightly bonded to the top surface of the grain placement area 51. Finally, the adsorption device 30 is moved away from the grain 20, and at the same time, the crystal bonding device 70 stops adsorbing the outside of the grain placement area 51 by the second negative pressure 62.

[0080] In summary, the method of the present invention can completely squeeze out the air in the gap 90 between the die 20 and the die placement area 51, completely eliminating the possibility of air bubbles being trapped between the die 20 and the die placement area 51, thus achieving the effect of preventing air bubble trapping. Therefore, there will be no voids between the die 20 and the die placement area 51, and subsequent processing procedures for picking or identifying the die 20 will not be affected by air bubbles, improving the yield of products manufactured in subsequent processing.

[0081] Preferably, the fixed base 31 is mounted on a displacement mechanism (not shown), which can control the position of the suction nozzle 32 by moving the fixed base 31. More specifically, step S100, as... Figure 7 As shown, the displacement mechanism can move the fixing seat 31 above the carrier film 10 and align it with the grain 20 on the target block 11; step S200, as... Figure 8A and Figure 8B As shown, the displacement mechanism can move the fixing seat 31 above the die placement area 51 and align the suction nozzle 32 with the die placement area 51; step S300, as... Figure 9A and Figure 9B As shown, the displacement mechanism can move the fixed base 31 downward and bring the suction nozzle 32 closer to the grain placement area 51; step S400, as... Figure 10A and Figure 10B As shown, after the bottom surface of the grain 20 is tightly attached to the top surface of the grain placement area 51, the displacement mechanism can move the fixing seat 31 upward and move the suction nozzle 32 away from the grain 20.

[0082] Preferably, step S400, such as Figure 10A and Figure 10B As shown, the vacuum device 60 stops evacuating the plurality of second pressure channels 72, the plurality of second pressure channels 72 no longer generate a vacuum, the vacuum device 60 no longer provides the second negative pressure 62, and thus the crystal bonding device 70 stops adsorbing the outer side of the crystal placement area 51 by means of the second negative pressure 62.

[0083] Preferably, step S300, such as Figure 9A and Figure 9B As shown, the curvature of the grain placement region 51 is greater than that of the grain 20. Therefore, the method of the present invention ensures that the center of the grain placement region 51 contacts the center of the grain 20, while the periphery of the grain placement region 51 does not contact the periphery of the grain 20, thus forming a gap 90 between the periphery of the grain placement region 51 and the periphery of the grain 20.

[0084] Preferably, step S300, such as Figure 9A and Figure 9B As shown, the width of the first air pressure channel 71 is equal to the width of the grain placement area 51. Therefore, the method of the present invention ensures that the positive pressure 81 is concentrated and blown entirely onto the grain placement area 51, without blowing to the outside of the grain placement area 51, and without the problem of the area around the grain placement area 51 not being blown by the positive pressure 81.

[0085] like Figure 11A and Figure 12A As shown, in a preferred embodiment, the adsorption device 30 is circular (i.e., both the fixing base 31 and the suction nozzle 32 are circular) and the groove 322 is circular in shape, the crystal bonding device 70 is circular and the first air pressure channel 71 is circular. Figure 11B and Figure 12B As shown, in another embodiment, the adsorption device 30A is rectangular (i.e., the fixing seat 31A and the suction nozzle 32A are both circular) and the groove 322A is rectangular in shape, the crystal bonding device 70A is rectangular and the first air pressure channel 71A is rectangular.

[0086] Furthermore, in a preferred embodiment, step S300, as... Figure 9A As shown, when the circular suction nozzle 32 adsorbs the grain 20, the curved grain 20 takes on a conical shape after being inserted into the groove 322. The positive pressure 81, after passing through the circular first air pressure channel 71, can form a circular airflow that blows through the grain placement area 51, causing the grain placement area 51 to bulge upwards into a conical shape. Because both the grain 20 and the grain placement area 51 are conical, the center of the grain placement area 51 contacts the center of the grain 20, but the center of the grain placement area 51 does not contact the periphery of the grain 20.

[0087] In another embodiment, in step S300, when the rectangular suction nozzle 32A adsorbs the grain 20, the curved grain 20, after being inserted into the groove 322A, takes on a square pyramid shape. The positive pressure 81, passing through the rectangular first air pressure channel 71A, forms a rectangular airflow that blows across the grain placement area 51, causing the grain placement area 51 to bulge upwards and take on a square pyramid shape. Because both the grain 20 and the grain placement area 51 are square pyramidal, the center of the grain placement area 51 contacts the center of the grain 20, but the center of the grain placement area 51 does not contact the periphery of the grain 20.

[0088] like Figures 13A to 13C As shown, in a preferred embodiment, in step S300, under the condition of uniform pressure of positive pressure 81, the stress balance of the grain placement area 51 is achieved by the positive pressure 81 blowing, causing the grain placement area 51 to bulge upwards. More specifically, as Figure 13A As shown, positive pressure 81 first establishes a uniform pressure at the center of the grain placement area 51, which is greater than the ambient pressure (i.e., one atmosphere); then, as... Figure 13B As shown, when the positive pressure 81 establishes a uniform pressure at the center of the grain placement region 51, the center of the grain placement region 51 will be the highest point of the bulge. The principle will be explained further below. Figure 13A As shown, assuming the thin film 50 is a uniform material and the die bonding device 70 has a symmetrical structure, a schematic model can be established to represent this state. For example... Figure 13C As shown, the boundary conditions are set to be fixed on both sides, and the entire grain placement region 51 is subjected to uniform stress. Therefore, the deformation of the grain placement region 51 can be derived using mechanics of materials. The deformation formula is:

[0089] The formula for the maximum deformation: ,at this time Where W is the pressure, L is the force-bearing width, E is the material elastic modulus, and I is the material moment of inertia. E and I are constants under uniform conditions. From the above mechanical formula, it can be seen that when the pressure is uniform, the highest point of deformation occurs at the center of the grain placement area 51. Basically, if the state of the grain placement area 51 is considered, the above mechanical formula would be a two-dimensional expression, but the derivation process would be more complex. Therefore, by assuming a one-dimensional expression, the constant remains that the highest point will always occur at the center of the grain placement area 51. In this way, the present invention can ensure that the center of the grain placement area 51 contacts the center of the grain 20, while the periphery of the grain placement area 51 does not contact the periphery of the grain 20, thus forming a gap 90 between the periphery of the grain placement area 51 and the periphery of the grain 20.

[0090] like Figure 14A and Figure 14B As shown, in other embodiments, in step S300, the pressure of the positive pressure 81 is greater closer to the axis of the die bonding device 70, causing the bulge of the grain placement area 51 to gradually increase from the periphery of the grain placement area towards the center. More clearly, as Figure 14A As shown, an annular body 73 divides the first air pressure channel 71 into a first chamber 711 and a second chamber 712. A through hole 731 is formed in the middle of the annular body 73, connecting the first chamber 711 and the second chamber 712, and the diameter of the through hole 731 is smaller than the diameters of the first chamber 711 and the second chamber 712. Figure 14A As shown, the average pressure of the positive pressure 81 in the first chamber 711 is... Figure 14B As shown, the positive pressure 81 enters the second chamber 712 after passing through the smaller diameter through hole 731. The pressure of the positive pressure 81 in the second chamber 712 increases as it gets closer to the axis of the die-bonding device 70. Therefore, the center of the die-placement area 51 experiences a greater thrust than its surroundings, causing the bulge of the die-placement area 51 to gradually increase from its periphery towards the center. In this way, the present invention ensures that the center of the die-placement area 51 contacts the center of the die 20, while the periphery of the die-placement area 51 does not contact the periphery of the die 20, thus forming a gap 90 between the periphery of the die-placement area 51 and the periphery of the die 20.

[0091] The above describes the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also within the scope of protection of the present invention.

Claims

1. A method for preventing grain transfer that encapsulates air bubbles, characterized in that, include: (a) An adsorption device adsorbs a crystal by a first negative pressure and moves it above a crystal placement area of ​​a thin film, the crystal being concave and bent inward; (b) A die-bonding device blows a positive pressure onto the die-placement area, causing the die-placement area to bulge upwards, with the center of the die-placement area contacting the center of the die, and a gap is formed between the periphery of the die-placement area and the periphery of the die; and (c) The adsorption device stops adsorbing the crystal by the first negative pressure, so that the crystal returns to a flat state and detaches from the adsorption device. At the same time, the crystal fixing device stops blowing the crystal placement area by the positive pressure, so that the crystal placement area returns to a flat state. During the process of the crystal and the crystal placement area returning to a flat state simultaneously, the crystal and the crystal placement area together squeeze the air in the gap outward, so that the gap is closed. After the gap is completely closed, the bottom surface of the crystal is tightly attached to the top surface of the crystal placement area.

2. The method for preventing grain transfer encapsulating bubbles according to claim 1, characterized in that, In step (b), the curvature of the grain placement region is greater than the curvature of the grain.

3. The method for preventing grain transfer encapsulating air bubbles according to claim 1, characterized in that, In step (b), under the pressure-averaged state of the positive pressure, the stress balance of the grain placement area is blown by the positive pressure, causing the grain placement area to bulge upward.

4. The method for preventing grain transfer encapsulating bubbles according to claim 1, characterized in that, In step (b), the closer to the axis of the die bonding device, the greater the pressure of the positive pressure, so that the degree of bulging of the grain placement area gradually increases from the periphery of the grain placement area towards the center.

5. The method for preventing grain transfer encapsulating air bubbles according to claim 1, characterized in that, The adsorption device includes a fixed base and a suction nozzle. The fixed base has a first vacuum channel connected to a vacuum device. The suction nozzle is located at the bottom of the fixed base and has a second vacuum channel and a groove. The second vacuum channel communicates with the first vacuum channel, and the groove communicates with the second vacuum channel. In step (a), the vacuum device evacuates the first vacuum channel, and the gas in the groove passes sequentially through the second vacuum channel and the first vacuum channel to generate a vacuum and provide the first negative pressure. The first negative pressure adsorbs the grain through the groove, causing the grain to bend inward and sink into the groove. In step (c), the vacuum device stops evacuating the first vacuum channel, and the first vacuum channel, the second vacuum channel and the groove no longer generate a vacuum. The vacuum device no longer provides the first negative pressure, and therefore the suction nozzle stops adsorbing the grain by the first negative pressure.

6. The method for preventing grain transfer encapsulating bubbles according to claim 1, characterized in that, The die bonding apparatus has a first pressure channel located in the middle of the die bonding apparatus and connected to a gas supply device; wherein, in step (b), the gas supply device supplies gas to the first pressure channel to generate airflow and provide positive pressure, the positive pressure blowing through the first pressure channel onto the grain placement area; and wherein, in step (c), the gas supply device stops supplying gas to the first pressure channel, the first pressure channel no longer generates airflow, the gas supply device no longer provides positive pressure, and thus the die bonding apparatus stops blowing through the grain placement area by the positive pressure.

7. The method for preventing grain transfer encapsulating bubbles according to claim 6, characterized in that, An annular body divides the first air pressure channel into a first chamber and a second chamber. A through hole is opened in the middle of the annular body, which connects the first chamber and the second chamber, and the diameter of the through hole is smaller than the diameter of the first chamber and the second chamber.

8. The method for preventing grain transfer encapsulating bubbles according to claim 6, characterized in that, The width of the first pressure channel is equal to the width of the grain placement area.

9. The method for preventing grain transfer encapsulating bubbles according to claim 1, characterized in that, In step (b), the die bonding device adsorbs the outer side of the grain placement area by a second negative pressure, and the adsorption device moves toward the grain placement area; and in step (c), the adsorption device is moved away from the grain, and the die bonding device stops adsorbing the outer side of the grain placement area by the second negative pressure.

10. The method for preventing grain transfer encapsulating bubbles according to claim 9, characterized in that, The die-bonding device has a plurality of second pressure channels, which are spaced apart along a circumferential direction and connected to a vacuum device; wherein, in step (b), the vacuum device evacuates the plurality of second pressure channels to generate a vacuum and provides the second negative pressure, which adsorbs the outer side of the grain placement area through the plurality of second pressure channels; and wherein, in step (c), the vacuum device stops evacuating the plurality of second pressure channels, the plurality of second pressure channels no longer generate a vacuum, the vacuum device no longer provides the second negative pressure, and thus the die-bonding device stops adsorbing the outer side of the grain placement area by the second negative pressure.

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