Method for realizing large-area metal bump transfer based on double-pulse laser-induced jetting

Abstract

The application discloses a kind of based on double-pulse laser-induced jet flow realizes large-area metal bump transfer printing method, belong to chip packaging technical field, including the following steps: step 1, obtain chip device phase pad arrangement;Step 2, prepare four receiving substrates;Step 3, solder is heated to be molten liquid metal;Step 4, erect laser emission device;Step 5, a receiving substrate is arranged in parallel above liquid metal;Step 6, planning laser scanning path;Step 7, based on double-pulse laser-induced jet flow realizes single metal droplet deposition on receiving substrate, according to laser scanning path, deposition is formed metal droplet array on receiving substrate;Step 8, replace receiving substrate;Step 9, make metal droplet melt reflow into spherical metal bump;Step 10, carry out four times transfer printing.The application can better take into account high-density bump integration requirement, preparation efficiency, overall cost and multiple indicators.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of chip packaging, and particularly relates to a method for realizing large-area metal bump transfer printing based on double-pulse laser-induced jet flow. BACKGROUND

[0002] With the progress of integration technology, the improvement of equipment and the use of sub-micron technology, the chip integration degree is continuously improved, the number of input / output pins increases sharply, the power consumption also increases, and the requirements for integrated circuit packaging are also more stringent. The packaging form of area array arrangement I / O bump—ball grid array packaging, chip scale packaging, wafer level chip scale packaging and flip chip packaging have appeared one after another, which places the chip with bump electrodes on the active area face down and directly bonds with the packaging substrate or wiring layer, thereby realizing metallurgical connection. This area array-based packaging method not only improves the utilization rate of silicon chips, but also has the advantages of short interconnection path, short signal transmission delay, small parasitic parameters, etc. In the 21st century, the number of transistors in the chip is still rising sharply, and the size of the traditional two-dimensional chip is constantly approaching the limit of Moore's law, so people seek to integrate chips in the vertical direction, and thus 3D packaging, also known as stacked chip packaging, appears. For this kind of packaging form mainly based on area array packaging, it can be collectively referred to as advanced packaging.

[0003] At present, advanced packaging technology is developing rapidly, and various packaging methods such as 2D, 2.5D, 3D, 3D+2D, 3D+2.5D have emerged, and the application fields include 5G, AI, wearable devices, high-performance servers, high-performance graphics cards, etc. In general, the purpose of advanced packaging is to improve the functional density, shorten the interconnection length, improve the system performance, and reduce the overall power consumption, and one of the most important links is the bump preparation. Metal micro-bump (or solder joint) as one of the important elements in advanced packaging plays a role in electrical interconnection and mechanical support in packaged devices.

[0004] The existing micro-bump array preparation methods can be mainly divided into two categories: one is to place pre-formed precision solder balls at specific positions on the substrate by special equipment to form a bump array, that is, the ball placement technology, typical processes include gravity ball placement method, laser ball placement method, etc.; the other is the direct preparation method of bump array, mainly including template printing method, evaporation method, electroplating method and jetting method, etc.

[0005] When preparing a bump array by gravity ball placement method, it is necessary to accurately place the pre-formed tin balls on the pads of the functional device. The gravity ball placement method needs to prepare a mask plate with the same arrangement as the pads in advance, then the mask plate and the pads are aligned, and the solder balls are placed on the designed pads by relying on their own gravity. This technology is simple to operate and can realize batch bump preparation at one time, but due to the limitation of the mask plate, it is easy to cause tin ball blockage and lead to ball missing problem, and it is difficult to realize small-pitch bump preparation.

[0006] Laser ball placement method as a non-contact soldering method, through the rotation of the ball separator, the single solder ball with a diameter slightly larger than the nozzle is transported to the nozzle, the solder ball at the nozzle is heated and melted by pulsed laser, and the melted solder is sprayed out by the back pressure inside the nozzle. This method can realize micron-level precision ball placement, and can be compatible with 0.04mm-7.6mm specification solder balls. However, the ball feeding method of the ball separator used in this technology leads to a low jetting frequency, usually only a few balls per second, and the nozzle structure is complex and the equipment cost is high.

[0007] Stencil printing method as the most commonly used direct preparation method of bump array, is suitable for the manufacture of bumps with a pitch of 200-400μm, has the advantages of high efficiency, low cost and being suitable for different types of solder alloy. However, this method faces great challenges in the preparation of fine-pitch high-density interconnection bumps with a pitch less than 150μm, and its application is limited due to the high cost of preparing small-pitch pad masks.

[0008] Evaporation method and electroplating method are also commonly used bump manufacturing methods, but the process is complex.

[0009] Nozzle jetting method as one of the bump preparation technologies that have attracted much attention in recent years, can realize continuous or on-demand jetting under the drive of piezoelectricity, air pressure, etc., has the advantages of low cost and simple ball placement process. However, due to the limitations of the equipment itself, the flexibility is poor, and it is difficult to take advantage of the high jetting efficiency; at the same time, it is difficult to control the flight process and deposition position of single micro-droplet, and there are difficulties in process control and poor consistency.

[0010] Based on the above problems, the present application provides a method for realizing large-area metal bump transfer printing based on double-pulse laser-induced jet flow, which can better balance the integration requirements, preparation efficiency, overall cost and other indicators of high-density bumps. SUMMARY

[0011] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a method for realizing large-area metal bump transfer printing based on double-pulse laser-induced jet flow.

[0012] To achieve the above purpose, the present application adopts the following technical solutions:

[0013] The method for realizing large-area metal bump transfer printing based on double-pulse laser-induced jet flow comprises the following steps:

[0014] Step 1, obtain the pad arrangement on the corresponding side of the chip device, divide the pad positions on the side of the chip device into four sub-zones, the first sub-zone is the pad position located in the odd row and the odd column, the second sub-zone is the pad position located in the odd row and the even column, the third sub-zone is the pad position located in the even row and the odd column, and the fourth sub-zone is the pad position located in the even row and the even column;

[0015] Step 2, prepare four transparent receiving substrates respectively for the deposition preparation of the large-area metal bumps corresponding to the pad positions in the corresponding sub-zones;

[0016] Step 3, heat the solder to a molten liquid metal state by using a heating furnace, and remove the residual oxide on the surface by using a scraper;

[0017] Step 4, set up a laser emitting device;

[0018] Step 5, fix a receiving substrate in parallel above the liquid metal, the distance between the receiving substrate and the metal liquid surface is h, and the receiving substrate is located between the laser emitting device and the metal liquid surface;

[0019] Step 6, according to the pad positions in the sub-zone corresponding to the receiving substrate, plan a laser scanning path, so that the positions of the double-pulse laser acting on the molten liquid metal surface and the pad positions in the corresponding sub-zone are one-to-one corresponding and the deposition of the metal micro-droplets on the receiving substrate is in a serpentine walking order;

[0020] Step 7, based on the double-pulse laser-induced jet flow, realize the deposition of a single metal micro-droplet on the receiving substrate, and deposit the metal micro-droplets on the receiving substrate in a serpentine walking order according to the laser scanning path in step 6 to form a metal micro-droplet array;

[0021] Step 8, replace the receiving substrate, and then enter step 6 until the metal micro-droplet arrays corresponding to the pad positions in the corresponding sub-zones are completed on the four receiving substrates;

[0022] Step 9, apply a low-residue no-clean flux on the metal micro-droplet arrays of all the receiving substrates, place the receiving substrates with the metal micro-droplet arrays on a constant-temperature heating platform, melt and reflow the metal micro-droplets into spherical metal bumps, and then cool the receiving substrates;

[0023] Step 10, place the four receiving substrates with the metal bumps on the chip device in turn for four times of transfer printing to realize the preparation of the required pads on the chip device; during each transfer printing, the metal bumps correspond to the corresponding pad positions one-to-one, and the metal bumps are transferred to the corresponding pad positions of the chip device by heating.

[0024] Preferably, the receiving substrate is a quartz glass substrate.

[0025] Preferably, the laser emitting device comprises a laser, a laser galvanometer and field lens system, and a computer, the laser and its laser galvanometer and field lens system are located at the upper part of the receiving substrate, the computer is connected to the laser, and the laser can irradiate different positions on the surface of the liquid metal through the adjustment of the laser galvanometer and field lens system.

[0026] Preferably, in step 5, the distance h between the receiving substrate and the liquid metal surface is 0.2-2 mm.

[0027] Preferably, in step 7, the method for depositing a single metal droplet on the receiving substrate based on double-pulse laser-induced jet flow is as follows:

[0028] The laser emitting device emits two laser pulses in sequence, the energy of the second laser pulse is not less than that of the first laser pulse, and the two laser pulses are reflected by the galvanometer of the laser emitting device and focused by the field lens to act on the same position on the surface of the liquid metal.

[0029] An elongated metal jet flow perpendicular to the metal surface is generated on the surface of the liquid metal, and the metal jet flow reaches the receiving substrate to form a metal droplet.

[0030] Preferably, the power density of the first laser pulse is 2.04×10 10 -2.04×10 12 W / m 2 , the energy is 0.001-2 mJ, the pulse width is 1 ps-1000 ns, and the laser wavelength is 100 nm-1400 nm.

[0031] The power density of the second laser pulse is 2.04×10 10 -2.04×10 12 W / m 2 , the energy is 0.001-2 mJ, the pulse width is 1 ps-1000 ns, and the laser wavelength is 100 nm-1400 nm.

[0032] The power density difference between the second laser pulse and the first laser pulse is 0-2×10 12 W / m 2 , and the energy difference is 0-1.8 mJ.

[0033] The time interval Δt between the first laser pulse and the second laser pulse is 10-100 μs.

[0034] The spot diameter of the first laser pulse and the second laser pulse is 10 μm-100 μm.

[0035] Preferably, the laser used by the laser emitting device is a nanosecond laser or a picosecond laser or a femtosecond laser.

[0036] Preferably, in step 10, the chip device is placed on a constant temperature heating platform for heating or heated by a hot air gun each time of transfer printing.

[0037] Preferably, the method of transfer printing using a constant temperature heating platform is as follows:

[0038] The constant temperature heating platform is turned on to heat, the chip device is placed on the constant temperature heating platform, and the receiving substrate carrying the metal bumps is reversely buckled on the chip device so that the metal bumps contact the chip device and are one-to-one aligned with the corresponding pad positions, and then the metal bumps on the receiving substrate are melted after heating and transferred to the pads to form ball-shaped solder joints.

[0039] Preferably, the method of transfer printing using a hot air gun is as follows:

[0040] The chip device is placed on a normal temperature platform with the corresponding pad surface facing up, the receiving substrate carrying the metal bumps is reversely buckled on the pad surface of the chip device so that the metal bumps contact the chip device and are one-to-one aligned with the corresponding pad positions, and then the hot air gun is started on the upper part of the receiving substrate to heat the receiving substrate, and the metal bumps are melted after heating and transferred to the pads to form ball-shaped solder joints.

[0041] The beneficial effects of the present application are as follows:

[0042] (1) The method of the present application only needs to plan the trajectory in advance, and then the ball-shaped solder joints can be formed through the preliminary preparation of the bumps, reflow and transfer printing, which can better balance the integration requirements of high-density bumps, preparation efficiency, overall cost and other indicators.

[0043] (2) When large-area metal bumps are prepared by the method of the present application, only the laser scanning trajectory and the laser action position are planned in advance according to the pad arrangement on the chip device, and the laser power density and pulse interval of the two pulsed lasers are planned according to the size of the metal bumps required. Compared with the gravity ball placement method which needs to prepare a mask plate in advance, the method of the present application does not have the problem of solder blocking the mask plate or missing points.

[0044] (3) The present application divides the pad positions into four sub-zones, and four receiving substrates are used to make metal bumps corresponding to the pad positions in the sub-zones, so that the metal bumps on the chip device are made in sub-zones. In addition, after the four sub-zones are divided, the distance between adjacent pad positions in each sub-zone is twice the distance between adjacent pad positions in the chip device, so that the distance between adjacent metal bumps made on each receiving substrate is twice the distance between adjacent pad positions in the chip device. The division of the four sub-zones of the pad positions on the chip device and the sub-zone making of the metal bumps in the present application increase the distance and reduce the density in the process of making the metal bumps, thereby reducing the difficulty of making. Compared with the stencil printing method, it is suitable for the preparation of small pad distance and high density bumps.

[0045] (4) The present application is based on the deposition of single metal micro-droplet on the receiving substrate by double-pulse laser-induced jet flow, and the deposition efficiency of the metal micro-droplet can reach several kilohertz or even higher. Compared with the laser ball planting method and the jet flow method, the method has higher efficiency.

[0046] (5) The method only needs to plan the trajectory in advance, and then the metal bumps can be prepared, reflowed and transferred. The process is simpler than the evaporation method and the electroplating method, and the overall cost is low. In addition, the deposition volume of the double-pulse laser-induced metal jet flow is the volume of the finally required prepared bump, and there is no material waste. Compared with the evaporation method and the electroplating method, the material utilization rate is extremely high. BRIEF DESCRIPTION OF DRAWINGS

[0047] The drawings accompanying the specification of the present application serve to provide a further understanding of the present application, and the illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute an improper limitation on the present application.

[0048] Figure 1 is a connection diagram of the laser emitting device in the present application;

[0049] Figure 2 is a distribution diagram of the pads in the full array type pad arrangement chip device in embodiment 2;

[0050] Figure 3 is a first sub-zone of the pad positions located at the odd-numbered row and the odd-numbered column on the chip device in embodiment 2 and a laser scanning path diagram thereof;

[0051] Figure 4 is an array diagram of the metal micro-droplets deposited on the receiving substrate corresponding to the pad positions in the first sub-zone in embodiment 2;

[0052] Figure 5 is a second sub-zone of the pad positions located at the odd-numbered row and the even-numbered column on the chip device in embodiment 2 and a laser scanning path diagram thereof;

[0053] Figure 6 is the array of metal droplets deposited on the receiving substrate corresponding to the pad locations on the second subzone in Example 2;

[0054] Figure 7 is the third subzone on the chip device and the laser scanning path corresponding to the pad locations on the third subzone in Example 2;

[0055] Figure 8 is the array of metal droplets deposited on the receiving substrate corresponding to the pad locations on the third subzone in Example 2;

[0056] Figure 9 is the fourth subzone on the chip device and the laser scanning path corresponding to the pad locations on the fourth subzone in Example 2;

[0057] Figure 10 is the array of metal droplets deposited on the receiving substrate corresponding to the pad locations on the fourth subzone in Example 2;

[0058] Figure 11 is the array of metal droplets deposited on the receiving substrate in Example 2;

[0059] Figure 12 is the array of metal droplets deposited on the receiving substrate in Example 2;

[0060] Figure 13 is the process of transferring the metal bumps on the receiving substrate to the pads on the chip device using a constant temperature heating platform in Example 2, (a) transferring the metal bumps on the receiving substrate corresponding to the pad locations on the first subzone to the pads on the chip device, (b) the array of metal bumps transferred to the pads on the chip device for the first time, (c) transferring the metal bumps on the receiving substrate corresponding to the pad locations on the other subzones to the pads on the chip device, (d) the array of metal bumps transferred to the pads on the chip device;

[0061] Figure 14 is the schematic diagram of the chip device when all the metal bumps are transferred to the chip device in Example 2, (a) the schematic diagram of the metal bumps on the chip device from the top, (b) the schematic diagram of the metal bumps on the chip device from the side;

[0062] Figure 15 is the distribution of the pads on the chip device with staggered pad arrangement in Example 3;

[0063] Figure 16 is the chip with different sizes and double full array type of stacked packaging in Example 4, (a) the arrangement of the pads on the lower surface of the chip, (b) the arrangement of the pads on the upper surface of the chip;

[0064] Figure 17is a schematic diagram of the process of transferring the reflowed metal bumps on the receiving substrate to the lower surface of the LGA chip by using a hot air gun in Example 4, (a) transferring the metal bumps on the receiving substrate to the lower surface of the LGA chip, (b) a diagram of the metal solder points transferred to the lower surface of the LGA chip;

[0065] Figure 18 is a schematic diagram of the process of transferring the reflowed metal bumps on the receiving substrate to the upper surface of the LGA chip by using a hot air gun in Example 4, (a) transferring the metal bumps on the receiving substrate to the upper surface of the LGA chip, (b) a diagram of the metal solder points transferred to the upper surface of the LGA chip;

[0066] wherein:

[0067] 1, chip device; 2, receiving substrate; 3, liquid metal; 4, constant temperature heating platform; 5, laser; 6, laser galvanometer and field lens system; 7, computer; 8, hot air gun; 9, normal temperature platform; 10, LGA chip; 11, heating furnace; 12, metal bump. DETAILED DESCRIPTION

[0068] It should be noted that the following detailed description is illustrative only, and is intended to provide further description in order to provide a further understanding of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0069] It is to be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments consistent with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0070] In the present application, the terms such as "upper", "lower", "bottom", "top" and the like indicate the orientation or positional relationship shown in the drawings, which is only a relationship word determined for the purpose of conveniently describing the structural relationship of the components or elements of the present application, and is not intended to specify any component or element in the present application, and cannot be understood as a limitation of the present application.

[0071] In the present application, the terms such as "connected", "connected" and the like should be understood broadly, which means that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. For relevant scientific or technical personnel in the art, the specific meaning of the above terms in the present application can be determined according to the specific circumstances, and cannot be understood as a limitation of the present application.

[0072] The application will be further described below in connection with the accompanying drawings and examples.

[0073] Example 1

[0074] The method for realizing large-area metal bump transfer printing based on double-pulse laser-induced jet flow comprises the following steps:

[0075] Step 1: Obtain the pad arrangement on the corresponding side of the chip device 1, and divide the pad positions on the side of the chip device 1 into four partitions, the first partition is the pad position located in the odd row and odd column, the second partition is the pad position located in the odd row and even column, the third partition is the pad position located in the even row and odd column, and the fourth partition is the pad position located in the even row and even column.

[0076] Step 2: Prepare four transparent receiving substrates 2 for the deposition preparation of large-area metal bumps corresponding to the pad positions in the corresponding partitions; by dividing the pad positions into four partitions, the four receiving substrates 2 are used to manufacture the metal bumps corresponding to the pad positions in the corresponding partitions, thereby realizing the partitioned manufacturing of the metal bumps on the chip device 1; in addition, after the four partitions are divided, the distance between the adjacent pad positions in each partition is twice the distance between the adjacent pad positions in the chip device 1, so that the distance between the adjacent metal bumps manufactured on each receiving substrate 2 is twice the distance between the adjacent pad positions in the chip device 1, that is, the division of the four partitions of the pad positions on the chip device 1 and the partitioned manufacturing of the metal bumps increase the distance and reduce the density in the manufacturing process of the metal bumps, thereby reducing the manufacturing difficulty.

[0077] Step 3: Use a heating furnace 11 to heat the solder to a molten liquid metal 3, and use a scraper to remove the residual oxide on the surface; the solder can be lead-free solder Sn96.5Ag3.0Cu0.5 or lead-containing solder Sn63Pb37, which is in a molten liquid metal state when heated to 240-260℃.

[0078] Step 4: Set up a laser emitting device;

[0079] Step 5: Fix a receiving substrate 2 parallel to the liquid metal 3 above, the distance between the receiving substrate 2 and the metal liquid surface is h, and the receiving substrate 2 is located between the laser emitting device and the metal liquid surface.

[0080] Step 6: According to the pad positions in the partition corresponding to the receiving substrate 2, plan the laser scanning path, so that the positions of the double-pulse laser acting on the molten liquid metal liquid surface and the pad positions in the corresponding partition are one-to-one corresponding and the metal droplet deposition is performed on the receiving substrate 2 in the order of serpentine walking; the technology of planning the laser scanning path to realize the metal droplet deposition in the order of serpentine walking is prior art, and the specific path planning method will not be described here.

[0081] Step 7, based on the double-pulse laser-induced jet flow to realize the deposition of single metal micro-droplet on the receiving substrate 2, according to the laser scanning path in step 6, the metal micro-droplet array is deposited on the receiving substrate 2 in the order of serpentine walking;

[0082] Step 8, replace the receiving substrate 2, and then enter step 6 until the metal micro-droplet array corresponding to the pad position on the corresponding partition is completed on the four receiving substrates 2;

[0083] Step 9, apply low-residue no-clean flux, such as FNC-3120, on the metal micro-droplet array of all receiving substrates 2, and place the receiving substrate 2 with the metal micro-droplet array on the constant temperature heating platform 4 at a temperature of 240℃, so that the metal micro-droplets melt and reflow into spherical metal bumps, and then cool the receiving substrate 2; wherein the receiving substrate 2 contacts the constant temperature heating platform 4, so that the metal micro-droplets melt and reflow, and the low-residue no-clean flux can effectively remove the metal oxides on the surface of the metal micro-droplets, so that the melted metal bumps rebound into spherical shape under the action of larger surface tension; based on the double-pulse laser-induced jet flow to realize the deposition of single metal micro-droplet on the receiving substrate 2, the deposited metal micro-droplets often spread, which is not suitable for spherical metal bumps for chip device packaging, and the present application forms spherical metal bumps suitable for chip device packaging by reflowing the metal micro-droplets in step 9;

[0084] Step 10, place the four receiving substrates 2 with metal bumps on the chip device 1 in turn for four times of transfer printing to realize the preparation of the required pads on the chip device 1; during each transfer printing, the metal bumps correspond to the corresponding pad positions one by one, and the metal bumps are transferred to the corresponding pad positions of the chip device 1 by heating.

[0085] Compared with the metal bumps 12 and the receiving substrate 2, the metal bumps 12 and the pads of the chip device 1 have better wettability, so that the metal bumps 12 can be transferred from the receiving substrate 2 to the pads during heating.

[0086] Preferably, the receiving substrate 2 is a quartz glass substrate.

[0087] Preferably, as shown in Figure 1 The laser emitting device includes a laser 5, a laser galvanometer and field lens system 6, and a computer 7, the laser 5 and its laser galvanometer and field lens system 6 are located above the receiving substrate 2, the computer 7 is connected with the laser 5, and the laser 5 can irradiate different positions on the surface of the liquid metal 3 through the adjustment of the laser galvanometer and field lens system 6.

[0088] Preferably, in step 5, the distance h between the receiving substrate 2 and the liquid metal 3 is 0.2-2 mm.

[0089] Preferably, in step 7, the method for depositing a single metal droplet on the receiving substrate 2 based on double-pulse laser-induced jet flow is as follows:

[0090] The laser emitting device emits two laser pulses in sequence, the energy of the second laser pulse is not less than that of the first laser pulse, and the two laser pulses are reflected by the galvanometer mirror and focused by the field lens to act on the same position on the surface of the liquid metal 3;

[0091] An elongated metal jet flow perpendicular to the surface of the liquid metal 3 is generated on the surface of the liquid metal 3, and the metal jet flow reaches the receiving substrate 2 and coalesces to form a metal droplet.

[0092] Metal droplet deposition process: laser focusing is realized by means of a field lens, the first laser pulse is focused and irradiated on the liquid solder with a flat surface, and a crown-shaped pit is rapidly generated at the laser irradiation position. Before the pit closes, the second laser pulse is irradiated inside the pit to induce the generation of a metal jet flow. The metal jet flow moves upward along the direction perpendicular to the surface of the liquid metal 3 and is precisely deposited on the receiving substrate 2. By means of the galvanometer mirror, the action positions of the two laser pulses can be flexibly controlled, and according to the pre-planned laser scanning trajectory and the set laser parameters, a metal droplet deposition array is realized on the receiving substrate 2 in a serpentine walking sequence, wherein the metal droplet deposition array corresponds one-to-one to the pad positions in the corresponding partition.

[0093] Preferably, the power density of the first laser pulse is 2.04×10 10 ~2.04×10 12 W / m 2 , the energy is 0.001-2 mJ, the pulse width is 1 ps-1000 ns, and the laser wavelength is 100 nm-1400 nm.

[0094] The power density of the second laser pulse is 2.04×10 10 ~2.04×10 12 W / m 2 , the energy is 0.001-2 mJ, the pulse width is 1 ps-1000 ns, and the laser wavelength is 100 nm-1400 nm.

[0095] The power density difference between the second laser pulse and the first laser pulse is 0-2×10 12 W / m 2 , and the energy difference is 0-1.8 mJ.

[0096] The time interval Δt between the first laser pulse and the second laser pulse is 10-100 μs.

[0097] The spot diameter of the first laser pulse and the second laser pulse is 10-100 μm.

[0098] After the laser parameters such as laser pulse energy and pulse interval are reasonably adjusted, the metal bumps with a volume of 0.034-4.195 nL can be finally prepared, i.e. the metal solder joints with a spherical diameter of about 40-200 μm can be finally prepared.

[0099] Preferably, the laser 5 used by the laser emitting device is a nanosecond laser or a picosecond laser or a femtosecond laser.

[0100] Preferably, in the step 10, the chip device 1 is placed on the constant-temperature heating platform 4 for heating or heated by using the hot air gun 8 each time the transfer is performed.

[0101] Preferably, the method for transfer using the constant-temperature heating platform 4 is as follows:

[0102] The constant-temperature heating platform 4 is turned on to heat the chip device 1 placed thereon, and the receiving substrate 2 carrying the metal bumps is reversely buckled on the chip device 1 so that the metal bumps contact the chip device 1 and are aligned with the corresponding pad positions one by one. Then the metal bumps on the receiving substrate 2 are melted after being heated and transferred to the pads to form the spherical solder joints.

[0103] Preferably, the method for transfer using the hot air gun 8 is as follows:

[0104] The chip device 1 is placed on the normal-temperature platform 9 with the corresponding pad surface facing upward, and the receiving substrate 2 carrying the metal bumps is reversely buckled on the pad surface of the chip device 1 so that the metal bumps contact the chip device 1 and are aligned with the corresponding pad positions one by one. Then the hot air gun 8 is started to heat the receiving substrate 2 at the upper part of the receiving substrate 2, and the metal bumps are melted after being heated and transferred to the pads to form the spherical solder joints.

[0105] Embodiment 2:

[0106] The method for large-area metal bump transfer based on double-pulse laser-induced jet flow in Embodiment 1 is used to realize the transfer of the solder joints in the single-layer full-array pad arrangement chip device. The distribution of the pads in the full-array pad arrangement chip device is as shown in FIG. 2, and the specific steps are as follows: Figure 2

[0107] ​Step 1, obtain the pad arrangement of the chip device 1, the diameter of a single pad is 150 μm, the distance between adjacent pads is 300 μm, the required solder ball diameter is 180 μm, and the full array shape chip pad is 20 rows x 20 columns, the pad positions on the chip device 1 are divided into four sub-zones, the first sub-zone is the pad position located in the odd row and the odd column, the second sub-zone is the pad position located in the odd row and the even column, the third sub-zone is the pad position located in the even row and the odd column, and the fourth sub-zone is the pad position located in the even row and the even column.

[0108] Step 2, four transparent receiving substrates 2 are prepared for the deposition preparation of the large-area metal bumps corresponding to the pad positions in the corresponding sub-zones, and the receiving substrate 2 adopts a quartz glass substrate.

[0109] Step 3, the lead-free solder Sn96.5Ag3.0Cu0.5 is heated to 250℃ by using a heating furnace 11, and after the solid solder is melted into a molten liquid metal, the residual oxide on the surface is removed by using a scraper.

[0110] Step 4, a laser emitting device is erected.

[0111] Step 5, one of the receiving substrates 2 is placed parallel above the liquid metal 3, the distance between the receiving substrate 2 and the metal liquid surface is 1 mm, and the quartz glass substrate is located between the laser emitting device and the metal liquid surface.

[0112] Step 6, according to the sub-zone pad positions corresponding to the receiving substrate 2, the laser scanning path is planned, so that the positions of the double-pulse laser acting on the molten liquid metal surface and the pad positions in the corresponding sub-zone are one-to-one corresponding and the metal micro-droplet deposition is carried out on the receiving substrate 2 in the order of the snake-shaped walking.

[0113] Step 7, based on the double-pulse laser-induced jet flow, the deposition of a single metal micro-droplet on the receiving substrate 2 is realized, and the metal micro-droplet array is deposited on the receiving substrate 2 in the order of the snake-shaped walking according to the laser scanning path in step 6; wherein:

[0114] The power density of the first laser pulse is 7.33 x 10 10 W / m 2 , the energy is 0.072 mJ, the pulse width is 500 ns, and the laser wavelength is 1064 nm; the power density of the second laser pulse is 1.43 x 10 12 W / m 2 , the energy is 1.4 mJ, the pulse width is 500 ns, and the laser wavelength is 1064 nm; wherein the power density difference between the second laser pulse and the first laser pulse is 1.357 x 10 12 W / m 2The energy difference is 1.328 mJ; the time interval Δt between the first laser pulse and the second laser pulse is 25 μs, and the spot diameter is 50 μm; after the laser parameters such as pulse energy and pulse interval are reasonably adjusted, a solder joint with a ball diameter of 180 μm can be finally prepared.

[0115] Step 8, replace the receiving substrate 2, and then enter step 6 until the metal micro-droplet array corresponding to the pad position on the corresponding partition is completed on the four receiving substrates 2.

[0116] The first partition on the chip device located at the odd-numbered row and odd-numbered column pad position and the laser scanning path thereof are as shown in Figure 3 The metal micro-droplet array deposited on the receiving substrate 2 corresponding to the pad position of the first partition is as shown in Figure 4 The second partition on the chip device located at the odd-numbered row and even-numbered column pad position and the laser scanning path thereof are as shown in Figure 5 The metal micro-droplet array deposited on the receiving substrate 2 corresponding to the pad position of the second partition is as shown in Figure 6 The third partition on the chip device located at the even-numbered row and odd-numbered column pad position and the laser scanning path thereof are as shown in Figure 7 The metal micro-droplet array deposited on the receiving substrate 2 corresponding to the pad position of the third partition is as shown in Figure 8 The fourth partition on the chip device located at the even-numbered row and even-numbered column pad position and the laser scanning path thereof are as shown in Figure 9 The metal micro-droplet array deposited on the receiving substrate 2 corresponding to the pad position of the fourth partition is as shown in Figure 10 Figure 3 Figure 5 Figure 7 Figure 9 The solid circles in the figure represent the double-pulse laser irradiation position, the solid track represents the planned laser scanning track, and the arrow direction represents the laser scanning direction; Figure 4 Figure 6 Figure 8 Figure 10 The solid black circles in the figure represent the metal micro-droplets deposited on the receiving substrate 2, and the dashed circles in the figure represent the positions corresponding to the presence of pads on the chip device but without the preparation of metal micro-droplets.

[0117] Step 9, apply FNC-3120 on the metal micro-droplet array of all receiving substrates 2, place the receiving substrate 2 with the metal micro-droplet array on the constant temperature heating platform 4 with a temperature of 240℃, so that the metal micro-droplets are melted and reflowed into spherical metal bumps, and then cool the receiving substrate 2; wherein the metal micro-droplet structure on the receiving substrate 2 is as shown in Figure 11 The spherical metal bumps on the receiving substrate 2 after reflow processing are as shown in Figure 12 ​​​​​​​​

[0118] Step 10, place four receiving substrates 2 with metal bumps on the chip device 1 in turn to perform four times of transfer printing to realize the preparation of the required solder joints on the chip device 1. In each transfer printing, the metal bumps correspond to the positions of the solder pads one by one, and the metal bumps are transferred to the corresponding positions of the solder pads on the chip device 1 by heating on the constant temperature heating platform 4. The process of transferring the reflowed metal bumps on the receiving substrate 2 to the solder pads on the chip device is shown in Figure 13 . Figure 13 , where (a) is the transfer of the metal bumps on the receiving substrate corresponding to the first partition solder joint position to the solder pads on the chip device; (b) is the metal solder joint transferred to the solder pads on the chip device for the first time; (c) is the transfer of the metal bumps on the receiving substrate corresponding to the solder joint position of other partitions to the solder pads on the chip device; (d) is the metal solder joint transferred to the solder pads on the chip device. The process of transferring the metal bumps on each receiving substrate 2 to the chip device is as follows: the constant temperature heating platform 4 is turned on to maintain a heating temperature of 240°C; the chip device 1 is placed on the constant temperature heating platform 4, and the receiving substrate 2 carrying the metal bumps is reversed and buckled on the chip device 1, so that the metal bumps contact the chip device 1 and align with the corresponding solder pad positions one by one; then the metal bumps on the receiving substrate 2 are melted after heating and transferred to the solder pads to form spherical solder joints. When the metal bumps are completely transferred to the chip device, it is shown in Figure 14 .

[0119] Example 3:

[0120] The method of Example 1 for transferring large-area metal bumps based on double-pulse laser-induced jet flow realizes the transfer of solder joints in a single-layer staggered pad arrangement chip device. The distribution of the solder joints in the staggered pad arrangement chip device is shown in Figure 15 . The specific steps are as follows:

[0121] Step 1, obtain the pad arrangement of the chip device 1, the diameter of a single pad is 50μm, the pitch between adjacent pads is 100μm, and the required solder ball diameter is 60μm. The chip device 1 has 20 rows x 20 columns of staggered chip pads. The pad positions on the chip device 1 are divided into four partitions, the first partition is the pad position located in the odd row and odd column, the second partition is the pad position located in the odd row and even column, the third partition is the pad position located in the even row and odd column, and the fourth partition is the pad position located in the even row and even column.

[0122] Step 2, prepare four transparent receiving substrates 2 for depositing and preparing large-area metal bumps corresponding to the pad positions in the corresponding partitions, and the receiving substrate 2 is made of quartz glass substrate.

[0123] Step 3, using furnace 11 to heat the lead-free solder Sn96.5Ag3.0Cu0.5 to 250℃, after the solid solder melts into molten liquid metal, use the scraper to remove the surface residual oxide.

[0124] Step 4, set up the laser emitting device.

[0125] Step 5, place a receiving substrate 2 parallel to the liquid metal 3, the distance between the receiving substrate 2 and the metal liquid surface is 0.2mm, and the quartz glass substrate is located between the laser emitting device and the metal liquid surface.

[0126] Step 6, according to the corresponding partition pad position of the receiving substrate 2, plan the laser scanning path, so that the double-pulse laser acts on the position corresponding to the pad position in the corresponding partition on the molten liquid metal surface, and the metal micro-droplet deposition is carried out on the receiving substrate 2 in the order of snake-shaped walking.

[0127] Step 7, based on the double-pulse laser-induced jet flow, the single metal micro-droplet is deposited on the receiving substrate 2, and the metal micro-droplet array is deposited on the receiving substrate 2 in the order of snake-shaped walking according to the laser scanning path in step 6; wherein:

[0128] The power density of the first laser pulse is 3.26×10 10 W / m 2 , the energy is 6.4μJ, the pulse width is 100ns, and the laser wavelength is 1064nm; the power density of the second laser pulse is 1.66×10 11 W / m 2 , the energy is 32.5μJ, the pulse width is 100ns, and the laser wavelength is 1064nm; wherein the power density difference between the second laser pulse and the first laser pulse is 1.33×10 11 W / m 2 , the energy difference is 26.1μJ; the time interval Δt between the first laser pulse and the second laser pulse is 15μs, and the spot diameter is 50μm; after reasonable adjustment of the laser parameters such as laser pulse energy and pulse interval, a solder joint with a ball diameter of 60μm can be finally prepared.

[0129] Step 8, replace the receiving substrate 2, and then enter step 6 until the metal micro-droplet array corresponding to the pad position on the corresponding partition is completed on the four receiving substrates 2.

[0130] Step 9, apply FNC-3120 on the metal micro-droplet array of all receiving substrates 2, place the receiving substrate 2 with the metal micro-droplet array on the constant temperature heating platform 4 with a temperature of 240℃, so that the metal micro-droplets melt and reflow into spherical metal bumps, and then cool the receiving substrate 2.

[0131] Step 10, four receiving substrates 2 with metal bumps are placed on the chip device 1 in turn for four times of transfer printing to realize the preparation of the required soldering points on the chip device 1. In each transfer printing, the metal bumps correspond to the corresponding soldering pad positions one by one, and the metal bumps are transferred to the corresponding soldering pad positions of the chip device 1 by heating through the constant temperature heating platform 4. The specific transfer printing process is the same as that in Example 3.

[0132] Example 4:

[0133] The method for realizing large-area metal bump transfer printing based on double-pulse laser-induced jet flow in Example 1 is used to realize the transfer printing of the soldering points in the size-different double-sided full-array type stacked packaging chip 10. The structure of the size-different double-sided full-array type stacked packaging chip is as shown in Figure 16 The specific steps are as follows:

[0134] For the full-array type soldering pads on the lower surface of the stacked packaging chip 10:

[0135] Step 11, the arrangement of the soldering pads on the lower surface of the stacked packaging chip 10 is obtained. The arrangement of the full-array type chip soldering pads on the lower surface is that the diameter of a single soldering pad is 120 μm, the distance between adjacent soldering pads is 250 μm, the required solder ball diameter is 150 μm, and there are 20 rows × 20 columns of soldering pads. The soldering pad positions are divided into four subareas. The first subarea is the soldering pad position located in the odd-numbered row and the odd-numbered column, the second subarea is the soldering pad position located in the odd-numbered row and the even-numbered column, the third subarea is the soldering pad position located in the even-numbered row and the odd-numbered column, and the fourth subarea is the soldering pad position located in the even-numbered row and the even-numbered column.

[0136] Step 12, for the chip lower surface soldering pad, four transparent receiving substrates 2 are prepared for the deposition and preparation of large-area metal bumps corresponding to the soldering pad positions in the corresponding subareas on the lower surface of the chip.

[0137] Step 13, the lead-free solder Sn96.5Ag3.0Cu0.5 is heated to 250℃ by using the heating furnace 11. After the solid solder is melted into molten liquid metal, the residual oxide on the surface is removed by using a scraper.

[0138] Step 14, the laser emitting device is erected.

[0139] Step 15, one receiving substrate 2 is placed parallel to the liquid metal 3. The distance between the receiving substrate 2 and the metal liquid surface is 0.8 mm. The quartz glass substrate is located between the laser emitting device and the metal liquid surface.

[0140] Step 16, according to the subarea soldering pad positions corresponding to the receiving substrate 2, the laser scanning path is planned so that the positions of the double-pulse laser acting on the molten liquid metal surface correspond to the soldering pad positions in the corresponding subareas one by one and the deposition of the metal micro-droplets on the receiving substrate 2 is in the order of the snake-shaped walking.

[0141] Step 17, based on the double-pulse laser-induced jet flow to realize the deposition of single metal micro-droplet on the receiving substrate 2, according to the laser scanning path in step 16, the metal micro-droplet array is deposited on the receiving substrate 2 in the order of the snake-shaped walking; wherein:

[0142] The power density of the first laser pulse is 7.64x10 10 W / m 2 , the energy is 30μJ, the pulse width is 200ns, and the laser wavelength is 1064nm; the power density of the second laser pulse is 1.15x10 12 W / m 2 , the energy is 0.45mJ, the pulse width is 200ns, and the laser wavelength is 1064nm; wherein the power density difference between the second laser pulse and the first laser pulse is 1.07x10 12 W / m 2 , the energy difference is 0.42mJ; the time interval Δt between the first laser pulse and the second laser pulse is 22μs, and the spot diameter is 50μm; after reasonable adjustment of the laser parameters such as laser pulse energy and pulse interval, the solder joint with a ball diameter of 150μm can be finally prepared.

[0143] Step 18, replace the receiving substrate 2, then enter step 16, until the metal micro-droplet array corresponding to the pad position on the corresponding partition on the four receiving substrates 2 is completed.

[0144] Step 19, apply FNC-3120 on the metal micro-droplet array of all receiving substrates 2, and place the receiving substrate 2 with the metal micro-droplet array on the constant temperature heating platform 4 with a temperature of 240℃, so that the metal micro-droplets are melted and reflowed into spherical metal bumps, and then the receiving substrate 2 is cooled.

[0145] Step 110, place the four receiving substrates 2 with metal bumps on the lower surface of the stacked packaging chip 10 in turn for four times of transfer printing, so as to realize the preparation of the required solder joints on the lower surface of the chip device 1; during each transfer printing, the metal bumps correspond to the corresponding pad positions one by one, and the metal bumps are transferred to the corresponding pad positions of the chip device 1 by heating with the hot air gun 8. The process of transferring the reflowed metal bumps on the receiving substrate 2 to the middle and lower surfaces of the stacked packaging chip 10 by the hot air gun 8 is shown in Figure 17 Figure 17 ​In the middle, (a) is the transfer of the metal bumps on the receiving substrate to the lower surface of the stacked package chip; (b) is the metal solder point transferred to the lower surface of the stacked package chip. The process of transferring the metal bumps on each receiving substrate 2 to the lower surface of the stacked package chip is as follows: place the stacked package chip 10 on the normal temperature platform 9 with its lower surface facing up, and place the receiving substrate 2 carrying the metal bumps upside down on the lower surface of the stacked package chip 10 so that the metal bumps contact the stacked package chip 10 and align with the corresponding pad positions one by one; then start the heat gun 8 on the upper part of the receiving substrate 2 to heat the receiving substrate 2, and the metal bumps melt after being heated and are transferred to the pads to form spherical solder points.

[0146] For the upper surface full array type pad in the stacked package chip 10:

[0147] Step 21, obtain the pad arrangement of the upper surface of the stacked package chip 10. The upper surface full array type chip pad arrangement is that the diameter of a single pad is 60 μm, the distance between adjacent pads is 120 μm, the required solder ball diameter is 70 μm, and there are 20 rows x 20 columns of pads; the pad positions are divided into four subareas, the first subarea is the pad position located in the odd row and odd column, the second subarea is the pad position located in the odd row and even column, the third subarea is the pad position located in the even row and odd column, and the fourth subarea is the pad position located in the even row and even column.

[0148] Step 22, for the upper surface pad of the chip, four transparent receiving substrates 2 are prepared for the deposition of large-area metal bumps corresponding to the pad positions in the corresponding subareas on the upper surface of the chip.

[0149] Step 23, use the heating furnace 11 to heat the lead-free solder Sn96.5Ag3.0Cu0.5 to 250℃, and after the solid solder is melted into molten liquid metal, remove the residual oxide on the surface with a scraper.

[0150] Step 24, set up a laser emitting device.

[0151] Step 25, place a receiving substrate 2 parallel to the liquid metal 3, the distance between the receiving substrate 2 and the metal liquid surface is 0.25 mm, and the quartz glass substrate is located between the laser emitting device and the metal liquid surface.

[0152] Step 26, according to the subarea pad positions corresponding to the receiving substrate 2, plan the laser scanning path so that the double-pulse laser acts on the positions of the molten liquid metal surface and the pad positions in the corresponding subareas one by one in the order of snake-shaped walking on the receiving substrate 2 to deposit metal droplets.

[0153] Step 27, based on the double-pulse laser-induced jet flow to realize the deposition of single metal micro-droplet on the receiving substrate 2, according to the laser scanning path in step 26, the metal micro-droplet array is deposited on the receiving substrate 2 in the order of the snake-shaped walking; wherein:

[0154] The power density of the first laser pulse is 7.64x10 10 W / m 2 , the energy is 30μJ, the pulse width is 200ns, and the laser wavelength is 1064nm; the power density of the second laser pulse is 1.53x10 11 W / m 2 , the energy is 60μJ, the pulse width is 200ns, and the laser wavelength is 1064nm; wherein the power density difference between the second laser pulse and the first laser pulse is 7.66x10 10 W / m 2 , the energy difference is 30μJ; the time interval Δt between the first laser pulse and the second laser pulse is 16μs, and the spot diameter is 50μm; after reasonable adjustment of the laser parameters such as laser pulse energy and pulse interval, the solder joint with a ball diameter of 70μm can be finally prepared.

[0155] Step 28, replace the receiving substrate 2, then enter step 26, until the metal micro-droplet array corresponding to the pad position on the corresponding partition on the four receiving substrates 2 is completed.

[0156] Step 29, apply FNC-3120 on the metal micro-droplet array of all receiving substrates 2, and place the receiving substrate 2 with the metal micro-droplet array on the constant temperature heating platform 4 with a temperature of 240℃, so that the metal micro-droplets are melted and reflowed into spherical metal bumps, and then the receiving substrate 2 is cooled.

[0157] Step 210, place the four receiving substrates 2 with metal bumps on the upper surface of the stacked packaging chip 10 in turn for four times of transfer printing to realize the preparation of the required solder joints on the upper surface of the stacked packaging chip 10; during each transfer printing, the metal bumps correspond to the corresponding pad positions one by one, and the metal bumps are transferred to the corresponding pad positions of the chip device 1 by heating with the hot air gun 8. The process of transferring the reflowed metal bumps on the receiving substrate 2 to the upper surface of the stacked packaging chip 10 by the hot air gun 8 is shown in Figure 18 , Figure 18In the middle, (a) is the metal bump on the receiving substrate transferred to the upper surface of the stacked package chip; (b) is the metal solder point transferred to the upper surface of the stacked package chip. The process of transferring the metal bump on each receiving substrate 2 to the upper surface of the stacked package chip is as follows: the stacked package chip 10 with the lower surface solder points transferred is placed on the normal temperature platform 9, with its upper surface upward, the receiving substrate 2 with the metal bump is reversed and buckled on the upper surface of the stacked package chip 10, so that the metal bump contacts the stacked package chip 10 and aligns with the corresponding pad position one by one; then the upper part of the receiving substrate 2 is started to heat the receiving substrate 2 by the hot air gun 8, the metal bump is melted after heating, and is transferred to the pad to form a spherical solder point.

[0158] Although the specific embodiments of the present application are described above with reference to the drawings, the present application is not limited to the above description, and various modifications or changes can be made by those skilled in the art without creative labor on the basis of the technical solutions of the present application.

Claims

1. A method for large-area metal bump transfer based on dual-pulse laser-induced jet, characterized in that, Includes the following steps: Step 1: Obtain the pad arrangement on the corresponding side of the chip device. Divide the pad positions on the side of the chip device into four partitions: the first partition is the pad positions located in odd-numbered rows and columns, the second partition is the pad positions located in odd-numbered rows and even-numbered columns, the third partition is the pad positions located in even-numbered rows and odd-numbered columns, and the fourth partition is the pad positions located in even-numbered rows and even-numbered columns. Step 2: Prepare four transparent receiving substrates, which are used for the deposition of large-area metal bumps corresponding to the pad positions on the corresponding partitions. Step 3: Heat the solder in a furnace until it becomes molten metal, and remove the residual oxides on the surface with a scraper; Step 4: Set up the laser emitting device; Step 5: Fix a receiving substrate parallel to the liquid metal above it, with the distance between the receiving substrate and the liquid metal surface being [missing information]. h The receiving substrate is located between the laser emitting device and the metal liquid surface; Step 6: Based on the location of the partitioned pads corresponding to the receiving substrate, plan the laser scanning path so that the position of the dual-pulse laser acting on the molten liquid metal surface corresponds one-to-one with the location of the pads in the corresponding partition, and deposit metal droplets on the receiving substrate in a serpentine sequence. Step 7: Deposit a single metal droplet on the receiving substrate using a dual-pulse laser-induced jet. Following the laser scanning path in Step 6, deposit the metal droplet array on the receiving substrate in a serpentine pattern. In step 7, the method for depositing a single metal microdroplet on the receiving substrate based on a dual-pulse laser-induced jet is as follows: The laser emitting device emits two laser pulses in succession. The energy of the second laser pulse is no less than that of the first laser pulse. The two laser pulses are reflected by the galvanometer and focused by the field mirror of the laser emitting device, so that they act on the same position on the surface of the liquid metal. The first laser pulse is focused onto the smooth liquid solder surface, and a crown-shaped pit is quickly generated at the laser irradiation point. Before the pit closes, the second laser pulse is irradiated into the pit, inducing the generation of a metal jet. The metal jet moves upward along a direction perpendicular to the liquid surface and is precisely deposited on the receiving substrate to form metal droplets. Step 8: Replace the receiving substrate, then proceed to step 6 until all four receiving substrates have completed the metal droplet array corresponding to the pad positions on the corresponding partitions. Step 9: Apply low-residue no-clean flux to the metal droplet array on all receiving substrates, place the receiving substrate with the metal droplet array on a constant temperature heating platform, and let the metal droplets melt and reflow into spherical metal bumps, and then cool the receiving substrate. Step 10: Place four receiving substrates with metal bumps on the chip device in sequence and perform four transfers to prepare the required solder joints on the chip device. During each transfer, the metal bumps correspond one-to-one with the corresponding pad positions. The metal bumps are transferred to the corresponding pad positions on the chip device by heating.

2. The method for large-area metal bump transfer based on dual-pulse laser-induced jet as described in claim 1, characterized in that, The receiving substrate is a quartz glass substrate.

3. The method for large-area metal bump transfer based on dual-pulse laser-induced jet as described in claim 1, characterized in that, The laser emitting device includes a laser, a laser galvanometer and field lens system, and a computer. The laser and its laser galvanometer and field lens system are located on the upper part of the receiving substrate. The computer is connected to the laser. The laser irradiates different positions on the liquid metal surface through the adjustment of the laser galvanometer and field lens system.

4. The method for large-area metal bump transfer based on dual-pulse laser-induced jet as described in claim 1, characterized in that, In step 5, the distance between the receiving substrate and the liquid metal surface h It is 0.2~2mm.

5. The method for large-area metal bump transfer based on dual-pulse laser-induced jet as described in claim 1, characterized in that, The power density of the first laser pulse is 2.04 × 10⁻⁶. 10 ~2.04×10 12 W / m 2 Energy ranges from 0.001 to 2 mJ, pulse width from 1 ps to 1000 ns, and laser wavelength from 100 nm to 1400 nm. The power density of the second laser pulse is 2.04 × 10⁻⁶. 10 ~2.04×10 12 W / m 2 Energy ranges from 0.001 to 2 mJ, pulse width from 1 ps to 1000 ns, and laser wavelength from 100 nm to 1400 nm. The power density difference between the second laser pulse and the first laser pulse is 0 ~ 2 × 10⁻⁶. 12 W / m 2 The energy difference is 0~1.8mJ; The time interval Δ between the first laser pulse and the second laser pulse t The duration is 10~100μs; The spot diameters of the first and second laser pulses are 10μm to 100μm.

6. The method for large-area metal bump transfer based on dual-pulse laser-induced jet as described in claim 3, characterized in that, The laser emitting device uses a nanosecond laser, a picosecond laser, or a femtosecond laser.

7. The method for large-area metal bump transfer based on dual-pulse laser-induced jet as described in claim 1, characterized in that, In step 10, each time the chip device is transferred, it is placed on a constant temperature heating platform for heating or heated using a hot air gun.

8. The method for large-area metal bump transfer based on dual-pulse laser-induced jet as described in claim 7, characterized in that, The method for transferring images using a constant temperature heating platform is as follows: The constant temperature heating platform is turned on. The chip device is placed on the constant temperature heating platform, and the receiving substrate with metal bumps is flipped onto the chip device so that the metal bumps contact the chip device and are aligned with the corresponding pads. Then, the metal bumps on the receiving substrate are heated and melted, and transferred to the pads to form spherical solder joints.

9. The method for large-area metal bump transfer based on dual-pulse laser-induced jet as described in claim 7, characterized in that, The method for transferring images using a heat gun is as follows: Place the chip device on a room temperature platform with the corresponding pads facing upwards. Then, place the receiving substrate with metal bumps upside down on the pads of the chip device, so that the metal bumps contact the chip device and are aligned with the corresponding pads. Then, a hot air gun is activated on the upper part of the receiving substrate to heat the receiving substrate. The metal bumps melt after heating and are transferred to the pads to form spherical solder joints.

Images