A flux, a substrate, and a method and apparatus for manufacturing the same.

Abstract

A flux, a substrate, and a method for manufacturing the same are disclosed. The flux comprises a bulk material and a powdered conductive material mixed in the bulk material, wherein the volume ratio of the conductive material to the flux is 5% to 10%. The substrate comprises: a substrate (1) including a plurality of pad groups (2); a plurality of electronic components (3) including pins (31, 32); and a connecting portion (4) located between the pads (21, 22) and the pins (31, 32) of the pad groups, wherein the connecting portion (4) comprises the conductive material in the flux. The method for manufacturing the substrate (1) comprises: providing a substrate (1) including a plurality of pad groups (2); manufacturing a plurality of electronic components (3) including pins (31, 32); printing flux onto the pads (21, 22) of the plurality of pad groups (2); and mechanically soldering the pads (21, 22) and the pins (31, 32). An apparatus including the substrate is also disclosed. The substrate is made with flux, which can significantly improve the solderability of electronic component pins to substrate pads.

Description

Technical Field

[0001] This disclosure relates to the field of electronic component soldering technology, and in particular to a flux, a substrate, and a method and apparatus for their fabrication. Background Technology

[0002] The bonding of electronic components to the substrate involves mounting the electronic components on the pads of the substrate, heating the circuit board in a reflow oven to melt the solder between the pads and the leads of the electronic components, thus bonding the electronic components to the substrate. Summary of the Invention

[0003] This disclosure provides a flux, a substrate, and a method and apparatus for manufacturing the same. The flux can improve the solderability of electronic components to the substrate and overcomes the problems of poor solderability, such as cold solder joints, high void rate of solder pads, and low push-pull force of low-thickness solder, that exist in existing fluxes.

[0004] Therefore, this disclosure provides a flux comprising a bulk material and a powdered conductive material mixed in the bulk material, wherein the volume ratio of the conductive material to the flux is 5% to 10%.

[0005] Optionally, in the flux provided in the embodiments of this disclosure, the conductive material includes at least one of tin metal, tin-silver alloy, tin-silver-copper alloy, and tin-bismuth alloy.

[0006] Optionally, in the flux provided in the embodiments of this disclosure, the bonding strength of the flux is 140g~180g.

[0007] Optionally, in the flux provided in the embodiments of this disclosure, the viscosity of the flux is 160 Pa·s to 210 Pa·s.

[0008] Optionally, in the flux provided in the embodiments of this disclosure, the bulk material includes rosin resin and its derivatives, synthetic resin surfactants, organic acid activators, corrosion inhibitors, co-solvents, and film-forming agents.

[0009] Accordingly, this disclosure also provides a substrate, comprising:

[0010] A substrate, the substrate comprising multiple pad groups;

[0011] Multiple electronic components, said electronic components including pins;

[0012] A connection portion, located between the pads of the pad group and the pins, the connection portion comprising a conductive material in the flux as described in any of the preceding claims.

[0013] Optionally, in the substrate provided in the embodiments of this disclosure, the orthographic projection of the conductive material in the flux on the substrate generally overlaps with the orthographic projection of the pads of the pad group on the substrate.

[0014] Optionally, in the substrate provided in the embodiments of this disclosure, the connecting portion further includes a tin-silver alloy or a tin-silver-copper alloy.

[0015] Accordingly, embodiments of this disclosure also provide an apparatus comprising the substrate described in any of the preceding claims.

[0016] Accordingly, this disclosure also provides a method for manufacturing a substrate as described in any of the foregoing embodiments, comprising:

[0017] Provide a substrate comprising multiple pad groups;

[0018] To fabricate multiple electronic components, including pins;

[0019] Apply the flux described in any of the above to the pads of the plurality of pad groups;

[0020] The pads and pins are soldered using mechanical force.

[0021] Optionally, the manufacturing method provided in the embodiments of this disclosure further includes: sputtering solder onto the pin; wherein the solder is a tin-silver alloy or a tin-silver-copper alloy.

[0022] Optionally, in the manufacturing method provided in the embodiments of this disclosure, the step of printing the flux described in any one of the above claims onto the pads of the plurality of pad groups specifically includes:

[0023] A steel mesh with multiple openings is placed on the substrate, the openings corresponding to the pads;

[0024] The flux described in any of the above items is printed into multiple openings of the stencil.

[0025] Optionally, in the manufacturing method provided in the embodiments of this disclosure, the step of using mechanical force to solder the pads and the pins specifically involves:

[0026] The plurality of electronic components are bonded to the thin film;

[0027] Multiple electronic components located on the thin film are transferred onto the substrate using mechanical force, with the pins of the electronic components corresponding to the pads;

[0028] The corresponding pads and pins are soldered using a reflow soldering process.

[0029] Optionally, in the manufacturing method provided in the embodiments of this disclosure, the film is a UV film or a blue film.

[0030] Optionally, in the manufacturing method provided in the embodiments of this disclosure, when the opening size of the steel mesh is 40μm~90μm, the particle size of the conductive material in the flux is 2μm~11μm;

[0031] When the opening size of the steel mesh is greater than 90μm, the particle size of the conductive material in the flux is 5μm~15μm. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a substrate provided in an embodiment of the present disclosure;

[0033] Figure 2 A flux printing effect diagram with a 2%-5% tin metal volume ratio provided in the embodiments of this disclosure;

[0034] Figure 3 A diagram illustrating the effect of flux solder joint voids with a 2%-5% tin metal volume ratio provided in the embodiments of this disclosure.

[0035] Figure 4 A flux printing effect diagram with a 5%-10% tin metal volume ratio provided in the embodiments of this disclosure;

[0036] Figure 5 A diagram illustrating the effect of flux solder joint voids with a 5%-10% tin metal volume ratio provided in this embodiment of the disclosure.

[0037] Figure 6 A flux printing effect diagram with a tin metal volume ratio of 15%-40% provided for an embodiment of this disclosure;

[0038] Figure 7 The image shows the bridging effect of flux solder joints with a tin metal volume ratio of 15%-40% provided in the embodiments of this disclosure;

[0039] Figure 8 This is a schematic diagram of the structure of a substrate provided in an embodiment of the present disclosure;

[0040] Figure 9 A flowchart illustrating a method for fabricating a substrate according to an embodiment of this disclosure;

[0041] Figure 10 A flowchart illustrating another method for fabricating a substrate according to an embodiment of this disclosure;

[0042] Figure 11 A flowchart illustrating another method for fabricating a substrate according to an embodiment of this disclosure. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description, in conjunction with the accompanying drawings, provides a specific embodiment of a flux, a substrate, and a method and apparatus for manufacturing the same.

[0044] The thickness and shape of each thin film in the attached figures do not reflect the actual ratio of flux and substrate; they are only intended to illustrate the contents of this disclosure.

[0045] In related technologies, the bonding of electronic components to a substrate generally requires the following steps:

[0046] (1) Moving electronic components to the correct location to be released, it is understood that this process may also involve moving the growth substrate (such as sapphire, Si, SiC, etc.) or the wafer (UV film or blue film) together with the electronic components;

[0047] (2) Electronic components are transferred from the original growth substrate or wafer to the receiving substrate by means of mechanical force (such as needle penetration), laser, van der Waals force, electromagnetic force, etc., wherein the receiving substrate is provided with a pad structure to be connected to the corresponding pins of the electronic components. In this step, the pins of the electronic components make contact with at least a partial area of ​​the corresponding pad structure.

[0048] (3) The connection between the electronic component pins and the pads on the receiving substrate is achieved by reflow soldering or other methods. Specifically, solder is placed between the pins and the pads, and a strong electrical connection is achieved by heating and curing the solder. It is understood that solder can be placed on either the pins of the electronic component or the pads on the substrate before step (2), so that step (3) is performed after step (2), thereby forming a strong electrical connection between the electronic component and the pads on the receiving substrate.

[0049] To ensure smooth soldering of electronic component leads to pads, flux is typically used to assist in the reflow soldering process. Flux is an auxiliary material used during soldering; its main function is to remove oxides from the solder and the surface of the base material, achieving the necessary cleanliness of the metal surface. Additionally, flux prevents re-oxidation of the surface during soldering, reduces solder surface tension, and improves soldering performance. In some embodiments, electronic components are transferred from the original growth substrate or wafer to the receiving substrate using a needle-punching method. By applying flux to the pads on the receiving substrate, the viscosity of the flux can temporarily adhere the electronic components peeled from the original growth substrate to the corresponding pads. However, since the flux evaporates during reflow soldering, if there is a misalignment between the electronic component and the corresponding pad, or if the solder thickness on the electronic component leads is insufficient, problems such as cold solder joints, high pad void ratios, and low push-pull force of thin solder may occur.

[0050] In view of this, embodiments of the present disclosure provide a flux comprising a bulk material and a conductive material mixed in the bulk material, wherein the volume ratio of the conductive material to the flux is 5% to 10%.

[0051] The flux provided in this disclosure significantly improves the solderability of electronic components (e.g., Mini / Micro LEDs) pins to substrate pads by mixing 5% to 10% by volume of conductive material into the bulk material. This overcomes problems such as poor solderability leading to cold solder joints, high pad void ratios, and low push-pull force of thin solder due to low solder thickness, which are inherent in existing fluxes. The flux provided in this disclosure can substantially improve product yield and reliability, and can also reduce solder thickness, thereby lowering the production cost of electronic components.

[0052] In specific implementations, the conductive material in the flux provided in the embodiments of this disclosure may include at least one of tin metal, tin-silver alloy, tin-silver-copper alloy, and tin-bismuth alloy.

[0053] The current soldering process generally includes applying solder to either the pins of the electronic component or the pads of the receiving substrate, applying flux to the pads of the receiving substrate, placing the electronic component on the corresponding pad of the receiving substrate, and then fixing the electronic component and the pads together by reflow soldering.

[0054] For example, such as Figure 1 As shown, a first pad group is provided on the substrate to be bonded to the pins of some electronic components (e.g., a microIC with 6 pins). The first pad group includes sub-pads O1, O2, O3, O4, O5, and O6. A second pad group is provided to be bonded to the pins of other electronic components (e.g., mini / microLEDs with 2 pins). The second pad group includes sub-pads R1- and R1+ to be bonded to the positive and negative pins of a first-color mini / microLED, respectively, and sub-pads R1+ to be bonded to the positive and negative pins of another first-color mini / microLED. Sub-pads R2- and R2+ are respectively bonded to the positive and negative pins, and sub-pads G1- and G1+ are respectively bonded to the positive and negative pins of a second-color mini / microLED, and sub-pads G2- and G2+ are respectively bonded to the positive and negative pins of another second-color mini / microLED, and sub-pads B1- and B1+ are respectively bonded to the positive and negative pins of a third-color mini / microLED, and sub-pads B2- and B2+ are respectively bonded to the positive and negative pins of another third-color mini / microLED.

[0055] In specific implementation, such as Figure 1 As shown, sub-pad O2 on the substrate is connected to sub-pads G1- and G2- via connecting lines; sub-pad O3 is connected to sub-pads B1- and B2- via connecting lines; sub-pad O4 is connected to scan line Cn via lateral connecting line Sn; sub-pad O5 is connected to data signal line Dm via via P1; sub-pad O6 is connected to reference signal line Vm via via P2; sub-pads R1+ and R2+ are connected to first positive signal line Hm1 via via P5; sub-pads G1+ and G2+ are connected to second positive signal line Hm2 via via P4; and sub-pads B1+ and B2+ are connected to second positive signal line Hm2 via via P4.

[0056] It is understandable that the connecting lines used to establish the connection between the sub-pads are located on the same film layer as the sub-pads. The difference is that a protective layer is set above the connecting lines, while the surface of the sub-pad area away from the substrate needs to be exposed in order to achieve bonding connection with electronic components.

[0057] The connecting lines used to realize the connection relationship between each sub-pad are located in different film layers from the scan line Cn, data signal line Dm, reference signal line Vm, first positive signal line Hm1 and second positive signal line Hm2. Insulating layers are set between them to separate them. The areas that need to be conductive between them can be electrically connected through vias located in the insulating layers.

[0058] The above is a repeating unit, and the substrate may include N. M repeating units, where 1≤n≤N and 1≤m≤M.

[0059] This disclosure focuses on the impact of conductive material content in flux, using tin metal as an example. The influence on soldering performance is verified by taking the volume ratio of tin metal to the total flux volume (Vtin:Vtotal) (2-40%) as an example. Figure 1 Taking a substrate with a first pad group (i.e., 6 pads) that are to be bonded to the pins of some electronic components (such as a micro IC with 6 pins) as an example, the distribution of tin metal in the flux of the fixedly connected electronic components and pads is inspected by microscope, and X-ray equipment is used to inspect the solder joint voids of the fixedly connected electronic components and pads, as follows:

[0060] Tin metal volume fraction (Vtin: Vtotal) 2%~5%: e.g. Figure 2 As shown, Figure 2 The diagram shows the distribution of sputtered tin metal 10 on sub-pads (O1-O6). Microscopic examination reveals that the tin metal 10 content on the sub-pads (O1-O6) is too low, failing to guarantee uniform distribution of tin metal 10 on each sub-pad (O1-O6). Figure 3 As shown, Figure 3 for Figure 2 The diagram shown illustrates the effect of the structure after reflow soldering. It can be seen that voids 20 exist on the sub-pads (O1-O6), accounting for approximately 20% of the total. The failure rate for cold solder joints is 0.4%, showing no improvement in soldering performance compared to that achieved with ordinary flux.

[0061] Tin metal volume ratio (V tin metal : V total) 5%~10%: e.g. Figure 4 As shown, Figure 4 This is a schematic diagram showing the distribution of sputtered tin metal 10 on the sub-pads (O1-O6). Microscopic examination shows that the tin metal 10 content is moderate and meets the theoretical requirements. The tin metal 10 is evenly distributed on the pads (O1-O6) without overlap. Figure 5 As shown, Figure 5 for Figure 4 The diagram shown illustrates the effect of the structure after reflow soldering. It can be seen that voids 20 exist on the sub-pads (O1-O6), with voids 20 accounting for 5-10%. The defect rate of cold solder joints is 0.005%, which is a significant improvement in soldering performance compared to ordinary flux.

[0062] Tin metal volume ratio (Vtin:Vtotal) 15%~40%: e.g. Figure 6 As shown, Figure 6 This is a schematic diagram of the distribution of sputtered tin metal 10 on the sub-pads (O1-O6). Microscopic examination revealed that the tin metal 10 content was excessive, exceeding the theoretical requirement, and the tin metal 10 was overlapping on the pads (O1-O6). Figure 7 As shown, Figure 7 for Figure 6 The diagram shown illustrates the effect of the structure after reflow soldering. It can be seen that voids 20 exist on the sub-pads (O1-O6), with voids accounting for 5% to 10%. However, there is uneven distribution of tin 10 between the pads (e.g., O1 and O2), resulting in bridging issues. The bridging failure rate is approximately 0.2%. The increased volume ratio of tin 10 affects the flux adhesion; as the volume ratio of tin 10 increases, the flux adhesion decreases, and the leakage rate of electronic component leads increases accordingly. Therefore, this solution cannot be adopted.

[0063] Therefore, it was ultimately determined that the volume of tin metal in the tin-containing flux should be between 5% and 10% of the total flux volume, and the specific volume content can be selected according to specific process requirements.

[0064] The transfer of electronic components from the original growth substrate to the receiving substrate using a needle-punching method relies on the adhesiveness of the flux to peel the electronic components off the original growth substrate. Therefore, the flux provided in this embodiment, which contains a certain volume ratio of conductive material (e.g., tin metal), must have sufficient adhesiveness to peel the electronic components off the original growth substrate. This embodiment tested different flux viscosities using the IPC-TM-650 Method 2.4.44 standard. The final test results determined that the flux's adhesion strength is 140g~180g to ensure sufficient adhesion between the flux and the electronic components before the reflow soldering process. If the adhesion strength is lower than 140g, poor adhesion may occur. Therefore, the flux provided in this embodiment has an adhesion strength of 140g~180g.

[0065] In specific implementation, the flux provided in the embodiments of this disclosure adopts the IPC-TM-650, Method 2.4.44 test standard, and the viscosity of the flux can be 160 Pa·s to 210 Pa·s. By setting a flux with a viscosity of 160 Pa·s to 210 Pa·s on the pads of the receiving substrate, the viscosity of the flux can be used to achieve temporary adhesion between the electronic components peeled off from the original growth substrate and the corresponding pads.

[0066] In specific implementation, the flux provided in the embodiments of this disclosure includes, but is not limited to, rosin resin and its derivatives, synthetic resin surfactants, organic acid activators, corrosion inhibitors, cosolvents, and film-forming agents.

[0067] It should be noted that, to ensure the conductive material (such as tin) is evenly mixed in the flux, it needs to be stirred for 5 minutes at 20 RPM using a solder paste mixer at room temperature. Of course, the specific speed and stirring time can be adjusted.

[0068] Based on the same inventive concept, this disclosure also provides a substrate, such as... Figure 8 As shown, it includes:

[0069] Substrate 1, which includes multiple pad groups 2;

[0070] Specifically, the substrate 1 can be made of a rigid material, such as glass, or a flexible material, such as polyimide. Each pad group 2 includes a pair of first pads 21 and second pads 22. Figure 8 Take pad group 2 as an example.

[0071] Multiple electronic components 3, including pins (31 and 32);

[0072] Specifically, electronic component 3 can be a light-emitting device, which may include a positive electrode pin 31 and a negative electrode pin 32. The number of pads in each pad group 2 is the same as the number of pins of an electronic component.

[0073] Connection part 4 is located between the pads and pins of the pad group 2. For example, there is a connection part 4 between the first pad 21 and the positive pin 31, and a connection part 4 between the second pad 22 and the negative pin 32. The connection part 4 includes the conductive material in the flux mentioned above.

[0074] The substrate provided in this embodiment can utilize the flux described above during its fabrication. This flux and solder form a connection during reflow soldering. Because the flux contains 5% to 10% conductive material by volume, the solderability between the electronic component leads and the substrate pads is significantly improved. This overcomes problems such as poor solderability leading to cold solder joints, high pad void ratios, and low push-pull force of thin solder due to low solder thickness, which are inherent with existing fluxes. The substrate provided in this embodiment has high product yield and reliability, and its fabrication process can reduce solder thickness, thereby lowering the production cost of electronic components.

[0075] With the continuous development of LED (Light Emitting Diode) technology, the size of LEDs is gradually shrinking. For example, light-emitting devices can be miniature LEDs (also known as sub-millimeter LEDs or micro LEDs). Mini-LEDs refer to LEDs with a size between 80 and 300 μm. When Mini-LEDs are used as pixels in a display panel to form a self-emissive display, a higher pixel density can be achieved compared to small-pitch LED displays. When Mini-LEDs are used as a light source in backlight modules, ultra-thin light source modules can be created through a denser arrangement of light sources; combined with local dimming technology, displays including Mini-LED backlight modules will have better contrast and high dynamic range lighting rendering effects. Micro LEDs, with a size smaller than 80 μm, can be directly used as pixels in display panels for near-eye, wearable, and handheld terminals.

[0076] Specifically, in this embodiment of the disclosure, an electronic component is used as the light-emitting device as an example. Figure 8 The substrate 1 in the text can refer to a substrate used to provide a light source or a substrate used for display, without limitation.

[0077] In specific implementation, in the substrate provided in the embodiments of this disclosure, such as Figure 8 As shown, the orthographic projection of the conductive material in the flux onto the substrate 1 roughly overlaps with the orthographic projection of the pads (21 or 22) of the pad group 2 onto the substrate 1, thereby ensuring the electrical connection between the pins and the pads. Specifically, the flux printing pattern can be adjusted according to process requirements.

[0078] In practical implementation, during the soldering process between the pins of the light-emitting device and the pads on the substrate, solder needs to be applied to the pins or pads to ensure electrical connection between the pins and pads. The solder and flux are then processed together in the reflow soldering process. For the pin-type transfer of the light-emitting device, the solder is generally applied to the pins of the light-emitting device, and the solder material is a tin-silver alloy or a tin-silver-copper alloy. Therefore, in the flux provided in the embodiments of this disclosure, such as... Figure 8 As shown, the connecting part 4 also includes a tin-silver alloy or a tin-silver-copper alloy. Specifically, the tin-silver alloy or tin-silver-copper alloy can have different alloy ratios, which can be adjusted according to process requirements.

[0079] Based on the same inventive concept, this disclosure also provides a method for manufacturing the aforementioned substrate, such as... Figure 9 The above includes:

[0080] S901, providing a substrate including multiple pad groups;

[0081] S902, Fabricating multiple electronic components including pins;

[0082] S903. Print the flux provided above onto the pads of multiple pad groups;

[0083] S904 uses mechanical force to solder the pads and leads.

[0084] The substrate fabrication method provided in this disclosure involves printing the flux provided in this disclosure onto the pads of multiple pad groups during the fabrication process. During the soldering process, the conductive material of the flux, such as tin metal, can be retained as part of the connection between the pin and the pad. Compared with the prior art where the flux almost completely evaporates, this disclosure can significantly improve the solderability of the pins of electronic components (such as light-emitting devices) to the pads of the substrate, and overcome the problems of poor solderability, high pad void rate, and low push-pull force of low-thickness solder caused by existing fluxes.

[0085] In specific implementation, the above-mentioned manufacturing method provided in the embodiments of this disclosure further includes: sputtering solder on the pin; the solder and flux are in physical contact during the soldering process, the bulk material of the flux except for tin metal volatilizes, and the tin metal and solder constitute the connection between the pin and the pad; wherein the solder can be a tin-silver alloy or a tin-silver-copper alloy.

[0086] In specific implementation, in the manufacturing method provided in the embodiments of this disclosure, the flux provided in the embodiments of this disclosure is printed onto the pads of multiple pad groups, such as... Figure 10 As shown, specifically it can be:

[0087] S1001. Place a steel mesh with multiple openings on a substrate, with the openings corresponding to the pads.

[0088] S1002. The flux provided in the embodiments of this disclosure is printed into multiple openings of the stencil.

[0089] Specifically, the opening and the pad can be in one-to-one correspondence, or one opening can correspond to multiple pads, depending on the process requirements.

[0090] In specific implementation, in the manufacturing method provided in the embodiments of this disclosure, mechanical force is used to solder the pads and pins, such as... Figure 11 As shown, specifically it can be:

[0091] S1101. Bonding multiple electronic components onto a thin film;

[0092] Specifically, the electronic components can be light-emitting devices, and the thin film can be a UV film or a blue film.

[0093] S1102. Multiple electronic components located on a thin film are transferred to a substrate using mechanical force, with the pins of the electronic components corresponding to the pads.

[0094] S1103. The corresponding pads and pins are soldered using a reflow soldering process.

[0095] In specific implementation, in the above manufacturing method provided in the embodiments of this disclosure, when the opening size of the steel mesh in step S901 is 40μm~90μm, the particle size of the conductive material in the flux can be 2μm~11μm;

[0096] Alternatively, when the opening size of the steel mesh in step S901 above is greater than 90μm, the particle size of the conductive material in the flux can be 5μm~15μm.

[0097] It should be noted that the embodiments disclosed herein use electronic components as light-emitting devices (such as LEDs) as an example to illustrate the soldering process of pins and pads, that is, the soldering process in which flux is applied to the light-emitting area. Of course, the flux provided in the embodiments of this disclosure can also be applied to components such as sensors located in the surrounding area.

[0098] Based on the same inventive concept, this disclosure also provides a display device, including: the substrate provided in the embodiments of this disclosure.

[0099] The display device can be a rigid display device or a flexible display device (i.e., bendable and foldable). The display device can be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigator. Other essential components of the display device are those that should be understood by those skilled in the art and will not be described in detail here, nor should they be construed as limiting this disclosure. The principle by which this display device solves the problem is similar to that of the aforementioned substrate; therefore, the implementation of this display device can be referred to the implementation of the aforementioned substrate, and repeated details will not be repeated here.

[0100] This disclosure provides a flux, substrate, and manufacturing method and apparatus thereof. By mixing 5% to 10% by volume of conductive material into the substrate material, the solderability of electronic components (such as the pins of light-emitting devices) to the substrate pads can be significantly improved. This overcomes problems such as poor solderability leading to cold solder joints, high pad void ratios, and low push-pull force of thin solder due to low solder thickness, which are present in existing fluxes. The flux provided in this disclosure can significantly improve product yield and reliability, and can also reduce solder thickness, thereby reducing the production cost of electronic components.

[0101] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A soldering flux, wherein, The flux includes a body material and a powdered conductive material mixed in the body material, the powdered conductive material including at least one of tin metal, tin-silver alloy, tin-silver-copper alloy, tin-bismuth alloy, the volume ratio of the conductive material to the flux being 5% to 10%, the flux having a tack force of 140 g to 180 g, the tack force being determined according to IPC-TM-650, Method 2.4.44, for peeling electronic components from a raw growth substrate; The flux has a viscosity of 160 Pa.S to 210 Pa.S, for temporarily adhering the electronic components peeled from the raw growth substrate to corresponding pads by setting the flux on the pads of a receiving substrate, using the tackiness of the flux.

2. The flux according to claim 1, wherein The body material includes rosin resin and derivatives thereof, synthetic resin surfactant, organic acid activator, corrosion inhibitor, cosolvent, film former.

3. A substrate, wherein, The flux includes: A substrate board including a plurality of pad groups; A plurality of electronic components including pins; A connecting portion between the pads of the pad groups and the pins, the connecting portion including the flux according to claim 1 or 2.

4. The substrate of claim 3, wherein, The conductive material in the flux has a normal projection on the substrate board substantially overlapping the normal projection of the pads of the pad groups on the substrate board.

5. The substrate of claim 3, wherein, The connecting portion further includes tin-silver alloy or tin-silver-copper alloy.

6. An apparatus, wherein, The substrate board includes the flux according to any one of claims 3 to 5.

7. A method of fabricating a substrate, wherein, The flux includes: Providing a substrate board including a plurality of pad groups; Manufacturing a plurality of electronic components including pins; Printing the flux according to claim 1 or 2 on the pads of the plurality of pad groups; Welding the pads and the pins by mechanical force.

8. The production method according to claim 7, wherein Further including: Sputtering solder on the pins, wherein the solder is tin-silver alloy or tin-silver-copper alloy.

9. The production method according to claim 7, wherein The printing of the flux according to claim 1 or 2 on the pads of the plurality of pad groups specifically includes: Placing a steel mesh having a plurality of openings on the substrate board, the openings corresponding to the pads; Printing the flux according to claim 1 or 2 into the plurality of openings of the steel mesh.

10. The method of manufacturing as defined in claim 7, wherein, The welding of the pads and the pins by mechanical force specifically includes: Bonding the plurality of electronic components on a film; Transferring the plurality of electronic components on the film to the substrate board by mechanical force, the pins of the electronic components corresponding to the pads; Welding the corresponding pads and the pins by reflow soldering process.

11. The production method according to claim 10, wherein The film is UV film or blue film.

12. The production method according to claim 9, wherein When the opening size of the steel mesh is 40 μm to 90 μm, the particle size of the conductive material in the flux is 2 μm to 11 μm; When the opening size of the steel mesh is greater than 90 μm, the particle size of the conductive material in the flux is 5 μm to 15 μm.

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