Method for preparing CSP lamp beads with chamfers, steel mesh and CSP lamp beads

Abstract

The present invention provides a method for preparing CSP lamp beads with chamfers, which relates to the field of semiconductor technology. The method comprises the following steps: printing a plurality of spaced transparent adhesive monomers on a substrate through a steel mesh; transferring a plurality of LED chips to the center of each of the transparent adhesive monomers, so that arc-shaped chamfers are formed around the LED chips; baking the transparent adhesive monomers to semi-solidify the transparent adhesive monomers; spraying a layer of white wall glue covering the LED chips on the substrate, and baking the white wall glue and the transparent adhesive monomers to solidify the white wall glue and the transparent adhesive monomers; dissociating the CSP lamp bead chamfer material from the substrate, and cutting two adjacent transparent adhesive monomers that have been solidified into one; peeling the plurality of transparent adhesive monomers into individual CSP lamp beads with chamfers, and encapsulating the CSP lamp beads with chamfers. The present invention also provides a steel mesh for preparing CSP lamp beads with chamfers and CSP lamp beads with chamfers.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for preparing a CSP lamp bead with a chamfer, a steel mesh, and the CSP lamp bead. Background Art

[0002] Packaging is the process of assembling integrated circuits into final chips. Simply put, it involves placing the bare IC die produced by the foundry onto a supporting substrate, routing the pins, and then securing the package to form a complete unit. Among various packages, CSP packaging achieves a chip area to package area ratio exceeding 1:1.14, which is very close to the ideal 1:1 ratio and is therefore the smallest package.

[0003] However, since CSP chips typically emit light from five sides, the surrounding encapsulation will weaken the chip's light output. Therefore, a transparent chamfer is often added around the chip to reflect light from the surrounding area and emit it outward, thereby enhancing the light output. The most common method for creating chamfers is to spray them onto the substrate surface using a glue dispenser. However, this method produces uneven chamfer shapes and large variations in the distance between the glue centers, making it difficult to perform subsequent packaging processes. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method for preparing CSP lamp beads with chamfers, a steel mesh and CSP lamp beads, aiming to improve the technical problems in the prior art, such as uneven chamfer shapes and large differences in colloid center distances, which are not conducive to the subsequent packaging process.

[0005] To achieve the above object, the present invention provides a method for preparing a CSP lamp bead with chamfered corners.

[0006] The steps include:

[0007] Printing a plurality of spaced transparent adhesive monomers on the substrate through a steel screen;

[0008] Transferring a plurality of LED chips to the center of each transparent adhesive unit, so that arc-shaped chamfers are formed around the LED chips;

[0009] baking the transparent adhesive monomer to semi-solidify the transparent adhesive monomer;

[0010] Spraying a layer of white wall glue covering the LED chip on the substrate, and baking the white wall glue and the transparent glue monomer to solidify the white wall glue and the transparent glue monomer;

[0011] Detaching the CSP lamp bead chamfer material from the substrate, and cutting the two adjacent transparent adhesive monomers that have been solidified into one;

[0012] The plurality of transparent adhesive monomers are peeled off to form single CSP lamp beads with chamfers, and the CSP lamp beads with chamfers are packaged.

[0013] Optionally, before the step of printing a plurality of spaced transparent adhesive monomers on the substrate through a steel screen, the method further includes:

[0014] A double-sided film is attached to the surface of the quartz glass, and a PET film is attached to the double-sided film;

[0015] Then, the quartz glass after film application is fixed in a printing jig;

[0016] Loading the steel screen on the printing press, setting the program, and loading the scraper;

[0017] Apply clear glue evenly underneath the spatula.

[0018] Optionally, the step of printing a plurality of spaced-apart transparent adhesive monomers on the substrate through a steel screen includes:

[0019] running the printing press and controlling the scraper to move twice in a forward and backward direction;

[0020] The transparent adhesive is pushed through the steel mesh and printed neatly and evenly on the surface of the PET film to form a plurality of transparent adhesive monomers arranged at intervals.

[0021] Optionally, the step of spraying a layer of white wall glue covering the LED chip on the substrate, and baking the white wall glue and the transparent glue monomer to solidify the white wall glue and the transparent glue monomer includes:

[0022] Using a dispensing machine to spray the white wall glue in the gaps between the LED chips at a height consistent with the LED chips;

[0023] The product was baked in an oven at 80° C. for 1 hour and then at 150° C. for 3 hours to completely cure the chamfer and the white wall glue.

[0024] Optionally, the method for preparing a CSP lamp bead with chamfered corners further comprises the following steps:

[0025] Disperse the phosphor powder into the transparent glue according to the set ratio and degas to form the fluorescent glue;

[0026] Evenly coating a layer of the fluorescent glue on the light-emitting surface of the LED chip;

[0027] Bake and cure in an oven at 150°C for 1 h.

[0028] Optionally, after the step of separating the CSP lamp bead chamfer material from the substrate and cutting the two adjacent transparent adhesive monomers that have been solidified into one, the method further includes:

[0029] Fixing the CSP lamp bead chamfer material on the UV film, using a cutter wheel cutter to cut the CSP lamp bead chamfer material to form a single CSP lamp bead, and dehumidifying;

[0030] A UV film is attached to the end surface of the white wall glue, and the UV film is pressed and flattened before being turned over;

[0031] Pour the single CSP lamp bead onto the new UV film, and irradiate the new UV film with UV to dissolve the glue.

[0032] Optionally, before the step of transferring the plurality of LED chips to the center of each transparent adhesive unit so that arc-shaped chamfers are formed around the LED chips, the step further includes:

[0033] Sputtering Ti with a thickness of 100 nm and then sputtering Cu with a thickness of 400 nm on the electrode portion of the LED chip to deposit a seed layer;

[0034] Pickling to remove CuO on the surface of the sputtered area of ​​the electrode, and then electroplating to deposit 35 μm Cu at the pad electrode position;

[0035] removing the seed layer using an etching solution;

[0036] Remove CuO above the electroplated Cu;

[0037] Cu+Ni / Au is electroplated at the pad electrode position.

[0038] In addition, to achieve the above-mentioned purpose, the present invention also proposes a steel mesh for preparing CSP lamp beads with chamfers, comprising a steel plate body, the steel plate body being rectangular, and the steel plate body being provided with a plurality of spaced printing holes, the printing holes penetrating the steel plate body in a vertical direction.

[0039] Optionally, the printing hole is a circular hole or a rectangular hole.

[0040] In addition, to achieve the above-mentioned purpose, the present invention further proposes a CSP lamp bead with chamfers, comprising:

[0041] substrate;

[0042] A light-emitting structure comprising an LED chip, wherein the LED chip is mounted on the substrate;

[0043] The reflective structure includes white wall glue, which is arranged around the LED chip and has an arc chamfered corner at the connection between the white wall glue and the LED chip, so that the light around the LED chip is reflected by the chamfered corner and emitted from the front, thereby enhancing the light intensity.

[0044] The technical solution provided by the present invention includes the following steps: printing a plurality of spaced-apart transparent adhesive monomers on a substrate using a steel screen; transferring a plurality of LED chips to the center of each transparent adhesive monomer, so that the LED chips have arc-shaped chamfers around them; baking the transparent adhesive monomers to semi-cure them; spraying a layer of white wall glue covering the LED chips on the substrate, and baking the white wall glue and the transparent adhesive monomers to cure them; separating the CSP lamp bead chamfer material from the substrate, and cutting two adjacent transparent adhesive monomers that have been solidified into one piece; peeling the plurality of transparent adhesive monomers into individual CSP lamp beads with chamfers, and encapsulating the CSP lamp beads with chamfers. The above method can quickly and stably produce a uniformly shaped and neatly arranged transparent colloid, providing a good foundation for subsequent processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0046] Figure 1 A schematic flow chart of an embodiment of a method for preparing a CSP lamp bead with chamfers provided by the present invention;

[0047] Figure 2 A schematic flow chart of an embodiment of a method for preparing a CSP lamp bead with chamfers provided by the present invention;

[0048] Figure 3 A schematic diagram of the structure of a steel mesh for preparing CSP lamp beads with chamfers provided by the present invention;

[0049] Figure 4 This is a schematic structural diagram of a CSP lamp bead with chamfered corners provided by the present invention.

[0050] Description of Figure Numbers:

[0051] Label Name Label Name

[0052] 100 steel mesh 200 CSP lamp beads with chamfers

[0053] 101 steel plate body 201 white wall glue

[0054] 102 printing hole 202 transparent adhesive monomer

[0055] 203 LED chips

[0056] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0057] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. The technical solutions in the present invention are clearly and completely described. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0058] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0059] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0060] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0061] When expressions such as “at least one of A, B, and C, etc.” are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, “a system having at least one of A, B, and C” should include but is not limited to systems having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, and C, etc.). When expressions such as “at least one of A, B, or C, etc.” are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, “a system having at least one of A, B, or C” should include but is not limited to systems having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, and C, etc.).

[0062] It should be noted that if a directional indication is involved in an embodiment of the present invention, the directional indication is only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0063] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0064] In the description of the present invention, it should be noted that the terms "upper", "lower", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0065] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0066] In addition, in the description of the present invention, unless otherwise specified, "plurality", "multiple roots" and "multiple groups" mean two or more.

[0067] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0068] In the prior art, the most common method for preparing chamfers is to use a dispensing machine to spray on the substrate surface. However, the chamfer shape prepared by this method is uneven, and the distance between the centers of the colloid also varies greatly, which is not conducive to the subsequent packaging process.

[0069] In view of this, the present invention provides a method for preparing CSP lamp beads with chamfers, a steel mesh and CSP lamp beads, aiming to solve the above problems. Figure 1 , Figure 1 The figure is a flow chart of an embodiment of a method for preparing a CSP lamp bead with a chamfer according to the present invention. In one embodiment, the method for preparing a CSP lamp bead with a chamfer comprises the following steps:

[0070] Step S10: Printing a plurality of spaced transparent adhesive monomers 202 on the substrate through the steel mesh 100 .

[0071] Step S20 : ​​transferring a plurality of LED chips 203 to the center of each of the transparent adhesive monomers 202 , so that arc-shaped chamfers are formed around the LED chips 203 .

[0072] Step S30 : baking the transparent adhesive monomer 202 to semi-solidify the transparent adhesive monomer 202 .

[0073] Step S40: spraying a layer of white wall glue 201 covering the LED chip 203 on the substrate, and baking the white wall glue 201 and the transparent glue monomer 202 to solidify the white wall glue 201 and the transparent glue monomer 202.

[0074] Step S50: separating the CSP lamp bead chamfer material from the substrate, and cutting the two adjacent transparent adhesive monomers 202 that are solidified into one.

[0075] Step S60 : peeling off the plurality of transparent adhesive units 202 into individual CSP lamp beads 200 with chamfers, and packaging the CSP lamp beads 200 with chamfers.

[0076] It should be noted that the product formed in the manufacturing process of step S10 to step S40 is called a CSP lamp bead chamfering material. After the CSP lamp bead chamfering material is processed through steps S50 to S60, a CSP lamp bead 200 with chamfers can be manufactured.

[0077] In this embodiment, by the process of printing chamfers on the steel mesh 100, this method can be used to quickly and stably obtain a transparent colloid with uniform shape and neat arrangement, providing a good foundation for subsequent processes. It should be noted that the available substrates include smooth films, high-temperature films, and frosted films; the available transparent adhesives include Jindi M6202D, Dow Corning CL-1000A, KMT0883B, and KMT0880B. Among them, Dow Corning CL-1000 and KMT0880B have uneven shapes after printing, while Jindi M6202D and KMT0883B maintain good shapes. Through continuous experiments, it is known that the dissociation performance of Jindi M6202D on the above three substrates is poor, but some chips on the frosted film can be dissociated together with the lens, and the frosted film will reduce the adhesion between the transparent adhesive and the substrate. KMT0883B still has chips bonded to the substrate on the smooth film, but the chips and lenses on the frosted film can be well dissociated.

[0078] Therefore, the optimal embodiment in this embodiment is to select KMT0883B as the transparent adhesive and a frosted film as the substrate.

[0079] Prepare the transparent adhesive and degas. It should be noted that adhesives are generally divided into single-component and multi-component adhesives. For single-component adhesives, simply weigh the required amount on a scale. For multi-component adhesives, use the scale according to the adhesive ratio provided by the adhesive manufacturer. Degassing is performed using a degassing centrifuge. The specific principle is as follows: after canning, air will mix into the glue, forming bubbles. The centrifuge's high-speed rotation can remove these bubbles from the glue, thereby achieving a dense texture. Multiple transparent adhesive units 202 are printed on the substrate using a steel mesh 100. Each transparent adhesive unit 202 is independent of the others. The specific steps for transferring and fixing the LED chip 203 between the transparent adhesive units 202 include: using a large-scale film arrangement machine, setting a transfer die bonding template based on the printed transparent adhesive distribution, adjusting the nozzle height, die removal, and die bonding positions, and enabling the die bonding image recognition function (which automatically adjusts the die bonding position if there are slight discrepancies). This allows the LED chip 203 to be transferred and bonded to the center of the adhesive. The LED chip 203 is fixedly mounted in the center of the transparent plastic unit 202 using a large chip placement machine, with the light-emitting surface of the LED chip 203 facing downward. This creates a circular chamfer around the LED chip 203. The circular chamfer acts as a lens, reflecting light from the surrounding area of ​​the lamp bead outward through the circular chamfer, thereby enhancing the light output intensity. This improves the brightness of the single-sided CSP lamp bead and increases the light extraction efficiency of the LED chip 203.

[0080] In step S30 , a Modian oven is used to bake at 80° C. for 30 minutes to put the transparent adhesive monomer 202 into a semi-cured state, so as to prevent the subsequent application of white wall adhesive 201 from destroying the uniform shape of the lens.

[0081] Before the printing process of the steel mesh 100, preliminary preparations need to be done. Therefore, the following steps are also included before step S10:

[0082] Step S1: sticking a double-sided film on the surface of the quartz glass, and then sticking a PET film on the double-sided film.

[0083] Step S2: Fixing the quartz glass after film lamination into a printing jig.

[0084] Step S3: Load the steel mesh 100 on the printing machine, set the program, and load the scraper.

[0085] Step S4: evenly apply transparent glue below the scraper.

[0086] It's understandable that quartz glass, with a hardness of up to 7 on the Mohs scale, offers advantages such as high-temperature resistance, low expansion coefficient, thermal shock resistance, chemical stability, and excellent electrical insulation. Therefore, we chose it as the substrate. Double-sided film is adhesive on both sides, while PET film is a frosted, high-temperature resistant film. Regarding why we first applied the double-sided film and then the frosted, high-temperature resistant PET film, we wanted to attach the frosted, high-temperature resistant PET film to the quartz glass surface. However, our existing frosted, high-temperature resistant PET film was not adhesive, so we needed to use a double-sided adhesive film as an intermediate adhesive. Currently, SMT printers are widely used in the electronics assembly industry. During the SMT printing process, printing jigs play a crucial role as devices for supporting and securing printed circuit boards.

[0087] In step S4, a transparent adhesive with high viscosity is prepared, vacuumed to remove bubbles, and evenly applied under the scraper.

[0088] After the preparations are completed, the printing of the stencil 100 can begin, wherein step S10 includes:

[0089] Step S101: operating the printing press and controlling the scraper to move twice in the forward and backward directions.

[0090] Step S102 : pushing the transparent adhesive through the steel mesh 100 and printing neatly and evenly on the surface of the PET film to form a plurality of transparent adhesive units 202 arranged at intervals.

[0091] It should be noted that SMT is surface assembly technology, also known as surface mount or surface mounting technology. It is the most popular technology and process in the current electronic assembly industry. It is a circuit assembly technology that installs pinless or short-lead surface mount components on the surface of a printed circuit board or other substrate, and assembles them by soldering through reflow soldering or dip soldering.

[0092] Furthermore, in this embodiment, after step S40, the following steps are further included:

[0093] Step S401 : using a dispensing machine to spray the white wall glue 201 in the gaps between the LED chips 203 to a height consistent with that of the LED chips 203 .

[0094] Step S402: using an oven to bake at 80° C. for 1 hour and then at 150° C. for 3 hours, so that the chamfer and the white wall glue 201 are completely cured.

[0095] In this embodiment, white wall glue 201 is prepared and degassed. The glue dispenser's dosage method quantitatively controls the amount of glue sprayed. By varying the dosage, the thickness of the glue in the sprayed area can be controlled. In step S402, the glue is baked in an oven at 80°C for one hour and then at 150°C for three hours to fully cure the chamfer and white wall glue 201. Furthermore, to prevent the glue from spreading after dispensing, an iron frame is used to surround the LED chip 203.

[0096] Furthermore, in this embodiment, the following steps are also included:

[0097] Step S70: dispersing the phosphor powder into the transparent glue according to a set ratio and degassing to form the fluorescent glue.

[0098] Step S80: uniformly coating a layer of the fluorescent glue on the light-emitting surface of the LED chip 203 .

[0099] Step S90: Bake and cure in an oven at 150° C. for 1 hour.

[0100] In this embodiment, the fluorescent glue is a mixture of glue and phosphor powder, with the specific ratio adjusted according to the desired color temperature. The fluorescent glue converts the blue light emitted by the chip into white light through the fluorescent glue. In one embodiment of this embodiment, the fluorescent glue is used in a ratio of 3.35g of glue + 0.882g of BL 304M2 yellow powder + 0.028g of RH610E red powder.

[0101] Further, see Figure 2 In this embodiment, step S50 further includes the following steps:

[0102] Step S501: fix the CSP lamp bead chamfer material on the UV film, use a cutter wheel cutter to cut the CSP lamp bead chamfer material to form a single CSP lamp bead, and dehumidify.

[0103] Step S502: affixing a UV film to the end surface of the CSP lamp bead chamfer material, pressing and flattening the UV film, and then performing film inversion.

[0104] Step S503: pour a single CSP lamp bead onto a new UV film, and irradiate the new UV film with UV to dissolve the glue.

[0105] It is understandable that when using the LED chip 203, placing the LED chip 203 on the UV film can keep the grain intact during cutting and reduce the breakage caused by cutting. Ensure that the grains will not be displaced or fall off during normal transportation, there will be no residual glue, it has appropriate expansibility, the grains are easy to remove, and water will not penetrate between the grains and the tape. After cutting with the UV film, the chip electrodes are generally facing upwards, so it is necessary to reverse the mold so that the chip electrodes are facing downwards to facilitate the next step of the solid crystal process. The role of UV degumming is to reduce the adsorption force of the film through ultraviolet light irradiation, which is convenient for the operation of subsequent processes.

[0106] The purpose of dehumidification is to remove the residual water from the previous wet cutting process. The specific process is to use an oven, set the baking parameters to 50℃ and 2 hours, and then place the material in the oven for baking.

[0107] In addition, in order to improve the stability of the CSP lamp bead, we thicken the electrode. In this embodiment, the method for preparing the CSP lamp bead with chamfered corners further includes the following steps:

[0108] Step S100: first sputtering Ti with a thickness of 100 nm on the electrode portion of the LED chip, and then sputtering Cu with a thickness of 400 nm to deposit a seed layer.

[0109] Step S110: removing CuO on the surface of the sputtered area of ​​the electrode by pickling, and then electroplating and depositing 35um Cu at the pad electrode position.

[0110] Step S120: using an etching solution to remove the seed layer.

[0111] Step S130: removing CuO on the electroplated Cu.

[0112] Step S140: electroplating Cu+Ni / Au at the pad electrode position.

[0113] It should be noted that electrode thickening is completed before packaging. The main process steps include seed layer deposition, Cu electroplating, seed layer etching, surface treatment, electroless NiAu plating, and conductivity testing. Seed layer deposition involves sputtering 100nm of Ti and then 400nm of Cu in preparation for Cu electroplating. Cu electroplating (electrode thickening) is followed by pickling to remove surface CuO before electroplating, followed by 35μm of Cu electroplating (Cu is plated at the pad electrode location, and the rest of the area is Cu as a seed layer). Seed layer etching is performed using an etchant to remove the seed layer. Surface treatment involves grinding and acid-base solution treatment (with a lower acidity than the pre-plating treatment) to remove CuO above the electroplated Cu. Electroless NiAu plating is performed (Cu+NiAu is plated at the pad electrode location, and SiO2 is plated elsewhere). A conductivity test is performed. Passing this test completes the electrode thickening process. The purpose of electrode thickening is to prevent blue leakage from the bottom of the LED after packaging, thereby improving packaging reliability. Ni / Au refers to electroless nickel plating (thickness greater than 3µm) followed by a thin gold layer (0.05-0.15µm) or a thick gold layer (0.3-0.5µm) on the PCB connector. The uniformity of the coating, good coplanarity, and the ability to provide a variety of soldering properties are driving its widespread application. Among the 0.05-0.1µm plating layers, gold (0.05-0.1µm) is used to protect the nickel during wire bonding.

[0114] In addition, in order to achieve the above-mentioned purpose of the invention, see Figure 3 The present invention further provides a steel mesh 100, comprising a steel plate body 101. The steel plate body 101 is rectangular and has a plurality of printing holes 102 spaced apart therefrom. The printing holes 102 vertically penetrate the steel plate body 101. The printing holes 102 may be circular or rectangular.

[0115] In addition, in order to achieve the above-mentioned purpose of the invention, see Figure 4 The present invention also provides a CSP lamp bead 200 with chamfers, comprising a substrate, a light-emitting structure, and a reflective structure; the light-emitting structure comprises an LED chip 203, which is mounted on the substrate; the reflective structure comprises a white wall glue 201, which surrounds the LED chip 203, and the white wall glue 201 forms an arc-shaped chamfer at the connection with the LED chip 203, so that the light around the LED chip 203 is reflected by the chamfer and emitted from the front, thereby enhancing the light output intensity.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention. The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a CSP lamp bead with chamfered corners, characterized in that: The steps include: Printing a plurality of spaced-apart transparent adhesive monomers on a substrate using a steel screen, wherein the substrate is a frosted PET film; Transferring a plurality of LED chips to the center of each transparent adhesive unit, so that arc-shaped chamfers are formed around the LED chips; Baking the transparent adhesive monomer to semi-cure the transparent adhesive monomer, wherein the semi-curing process includes baking at a temperature of 80° C. for 30 minutes; Spraying a layer of white wall glue covering the LED chip on the substrate, and baking the white wall glue and the transparent glue monomer to cure the white wall glue and the transparent glue monomer, wherein the curing process includes first baking at a temperature of 80° C. for 1 hour and then baking at 150° C. for 3 hours; Detaching the CSP lamp bead chamfer material from the substrate, and cutting the two adjacent transparent adhesive monomers that have been solidified into one; peeling off the plurality of transparent adhesive monomers into individual CSP lamp beads with chamfers, and packaging the CSP lamp beads with chamfers; Then, a layer of fluorescent glue is evenly applied on the light-emitting surface of the LED chip, and the fluorescent glue is cured; The step of transferring the plurality of LED chips to the center of each transparent adhesive unit so that arc-shaped chamfers are formed around the LED chips further includes: Sputtering Ti with a thickness of 100 nm and then sputtering Cu with a thickness of 400 nm on the electrode portion of the LED chip to deposit a seed layer; Acid pickling was performed to remove CuO on the surface of the sputtered area of ​​the electrode, and then 35 μm Cu was electroplated at the pad electrode position; removing the seed layer using an etching solution; Remove CuO above the electroplated Cu; Cu+Ni / Au is electroplated at the pad electrode position.

2. The method for preparing a CSP lamp bead with chamfers according to claim 1, wherein: Before the step of printing a plurality of spaced transparent adhesive monomers on the substrate through a steel screen, the method further includes: A double-sided film is attached to the surface of the quartz glass, and a PET film is attached to the double-sided film; Then, the quartz glass after film application is fixed in a printing jig; Loading the steel screen on the printing press, setting the program, and loading the scraper; Apply clear glue evenly underneath the spatula.

3. The method for preparing a CSP lamp bead with chamfers according to claim 2, wherein: The steps of printing a plurality of spaced transparent adhesive monomers on a substrate through a steel screen include: running the printing press and controlling the scraper to move twice in a forward and backward direction; The transparent adhesive is pushed through the steel mesh and printed neatly and evenly on the surface of the PET film to form a plurality of transparent adhesive monomers arranged at intervals.

4. The method for preparing a CSP lamp bead with chamfers according to claim 1, wherein: The steps of spraying a layer of white wall glue covering the LED chip on the substrate and baking the white wall glue and the transparent glue monomer to solidify the white wall glue and the transparent glue monomer include: Using a dispensing machine to spray the white wall glue in the gaps between the LED chips at a height consistent with the LED chips; The product was baked in an oven at 80° C. for 1 hour and then at 150° C. for 3 hours to completely cure the chamfer and the white wall glue.

5. The method for preparing a CSP lamp bead with chamfers according to claim 1, wherein: After the steps of separating the CSP lamp bead chamfer material from the substrate and cutting the two adjacent transparent adhesive monomers that have been solidified into one, the method further includes: Fixing the CSP lamp bead chamfer material on the UV film, using a cutter wheel cutter to cut the CSP lamp bead chamfer material to form a single CSP lamp bead, and dehumidifying; A UV film is attached to the end surface of the white wall glue, and the UV film is pressed and flattened before being turned over; Pour a single CSP lamp bead onto a new UV film, and irradiate the new UV film with UV to dissolve the glue.

6. A CSP lamp bead with chamfered corners, characterized in that: The CSP lamp bead with chamfered corners is prepared by the method for preparing a CSP lamp bead with chamfered corners according to any one of claims 1 to 5, and the CSP lamp bead with chamfered corners comprises: substrate; A light-emitting structure comprising an LED chip, wherein the LED chip is mounted on the substrate; The reflective structure includes white wall glue, which is arranged around the LED chip and has an arc chamfered corner at the connection between the white wall glue and the LED chip, so that the light around the LED chip is reflected by the chamfered corner and emitted from the front, thereby enhancing the light intensity.

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