A method for preparing an LED bracket with selective plating on the surface of a substrate

Abstract

The present invention discloses a method for preparing an LED bracket with selective plating on the surface of a substrate, including the steps of selective plating, substrate molding, injection molding, and degumming. The electroplating process is placed in front, and a shield is set on the front side of the metal substrate that needs to be electroplated. The shield can prevent the surface of the area that does not need to be electroplated from being penetrated by the electroplating solution and plated with a metal reflective layer, so that the electroplating area can be more effectively controlled. Compared with the traditional comprehensive electroplating method, it can save the use of precious metals, make it easier to recycle the electroplating solution, reduce the production cost, and solve the problem of waste of precious metals in the electroplating solution and difficulty in recycling in the past. The selective plating method can also allow the metal substrate to retain a large area that has not been electroplated, and the unplated area has a higher and firmer bonding force with the injection molding material, greatly improving the reliability of semiconductor packaging.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a method for preparing an LED bracket with selective plating on the surface of a substrate. Background Art

[0002] Patent application number CN2012101197520 discloses a pre-production process for LED lead frames. The pre-production process sequentially includes etching or punching, sealing, debonding, and electroplating. This pre-production process is a post-plating method, with the electroplating step being the last step. This post-plating method requires the entire lead frame to be plated in a plating tank, which requires a large amount of plating solution. After plating, the residual plating solution must be rinsed and recovered. This leads to high processing costs, difficulty in precious metal recovery, and high precious metal usage. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preparing an LED bracket with selective plating on the surface of a substrate. The LED bracket is prepared by first selective plating and then etching and injection molding, which solves the problem of waste of precious metals in electroplating solutions and difficulty in recycling.

[0004] The present invention provides a method for preparing an LED bracket with selective plating on the surface of a substrate, comprising the following steps:

[0005] Step A, selective plating: First, prepare a shield according to the electroplating requirements, with a plurality of electroplating holes in the shield. Then, attach the shield to the front side of the metal substrate to be electroplated. Then, electroplate the metal substrate with the shield attached to form a metal reflective layer at the positions on the front side of the metal substrate corresponding to the electroplating holes. After the electroplating is completed, remove the shield.

[0006] Step B, forming the substrate, forming the metal substrate after electroplating in step A by etching or punching, so that the metal substrate is formed with a plurality of grooves and hollow portions that are interconnected;

[0007] Step C, injection molding, wherein the metal formed in step B is injection molded through an injection molding device. After the injection molding material cools and solidifies, the grooves and hollow portions of the metal substrate are filled with the injection molding material, and a reflective cup is formed on the front side of the metal substrate.

[0008] Step D, debonding, is to debond the surface of the metal substrate after injection molding in step C.

[0009] The shield in step A is made of silicone or a membrane structure.

[0010] Wherein, the metal substrate in step A is a copper substrate or an iron substrate.

[0011] Wherein, the LED bracket substrate in step B is prepared by etching.

[0012] Wherein, in step B, the following steps are included:

[0013] Step a, primary dust removal, first perform dust removal on the front and back sides of the electroplated metal substrate, place the metal substrate into a dust collecting machine for dust removal, and the pressure of the dust collecting machine's sticky paper is 0.2-0.4 MPa;

[0014] Step b, preheating, the dust-removed metal substrate enters the preheating machine for preheating, the preheating temperature is 90-110°C;

[0015] Step c, attaching the dry film: the preheated metal substrate enters the laminating machine, and the dry film is pressed on the front and back sides of the metal substrate. The conveying speed of the laminating machine is 2.3-3.3 m / min, the temperature of the hot laminating wheel used for laminating is 110-120°C, and the pressure of the hot laminating wheel is 0.3-0.5 MPa. The temperature of the laminating strip used for cutting is 40-60°C.

[0016] Step d, exposure: after the dry film is attached to the metal substrate, a portion of the dry film is exposed to light to form a pattern on the dry film;

[0017] Step e, developing, removing the unexposed areas of the dry film with a developer, wherein the developer is a potassium carbonate solution having a mass concentration of 8 to 14 g / L;

[0018] Step f, washing once, using pure water to clean the developer remaining on the surface of the dry film;

[0019] Step g, etching, using an etching solution to etch the metal substrate into hollow portions and grooves, the etching solution comprising the following components in mass concentrations: Cu 2+ The concentration is 120-150 g / L, the hydrochloric acid concentration is 0.7-1.3 mol / L, and the rest is pure water;

[0020] Step h, secondary water washing, using pure water to clean the etching solution remaining on the metal substrate;

[0021] Step i, removing the dry film, using a film removal accelerator to remove the dry film on the front and back sides of the metal substrate;

[0022] Step j, washing three times with water to clean the film removal accelerator remaining on the metal substrate with pure water;

[0023] Step k, pickling, using pickling solution to clean the residual film removal accelerator, the pickling solution can be 3-5% sulfuric acid, 6-20g / L hydrogen peroxide and Cu 2+ One or a combination of two or more micro-etching solutions with a concentration of 5 to 45 g / L;

[0024] Step 1: washing the metal substrate with water four times, using pure water to clean the acid wash solution remaining on the metal substrate;

[0025] Step m: drying, drying the metal substrate at a temperature of 80-100° C. to form an LED bracket substrate;

[0026] Step n: performing a half-etching roughening treatment on the LED bracket substrate prepared in step m.

[0027] Wherein, in step n, the following steps are included:

[0028] Step S1, pure water cleaning, using pure water to clean the LED bracket substrate prepared in step n;

[0029] Step S2, degreasing, degreasing the LED bracket substrate cleaned in step S1 with sulfuric acid having a concentration of 3-5%;

[0030] Step S3: Super roughening: spray the roughening liquid onto the area of ​​the LED bracket substrate to be roughened. The super roughening temperature is 24-28°C. The Cu content of the roughening liquid is 0.01%. 2+ The concentration is 15-45 g / L, and the micro-etching amount is 0.6-1 μm;

[0031] Step S4, pickling, the pickling solution is hydrochloric acid solution, wherein the concentration of hydrochloric acid is 3-4%, Cu 2+ Content ≤ 2g / L, pickling temperature 80~100℃;

[0032] Step S5, drying, drying the LED bracket substrate at a temperature of 80-100° C.;

[0033] Step S6: water breakage test: the LED bracket base after pickling is subjected to a water breakage test, and the water exposure time is ≥30s.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The electroplating process is moved forward by setting a shield on the front side of the metal substrate that needs to be electroplated. The shield can prevent the surface of the area that does not need to be electroplated from being penetrated by the electroplating solution, which can more effectively control the electroplating area. Compared with the traditional full electroplating method, it can save the use of precious metals, make it easier to recycle the electroplating solution, reduce production costs, and solve the previous problems of precious metal waste and difficulty in recycling in the electroplating solution.

[0036] (2) The selective plating method can retain a large area of ​​the metal substrate that is not electroplated. The unplated area has a stronger bonding strength with the injection molding material, which greatly improves the reliability of semiconductor packaging.

[0037] (3) The preparation method is reasonably designed and has the characteristics of low comprehensive manufacturing cost and high product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the structure of the metal substrate in the embodiment;

[0039] Figure 2 2 is a schematic structural diagram of a shield in an embodiment;

[0040] Figure 3 2 is a schematic diagram of the structure of the metal substrate after the mask is covered in the embodiment;

[0041] Figure 4 Schematic diagram of the structure of the metal substrate after etching in the embodiment;

[0042] Figure 5 2 is a schematic structural diagram of an LED bracket in an embodiment;

[0043] Figure 6 is a cross-sectional view of an LED bracket in an embodiment;

[0044] Figure 7 yes Figure 6 Enlarged view of point A in the middle. DETAILED DESCRIPTION

[0045] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0046] In the description of the present invention, it should be noted that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" indicate orientations or positional relationships 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.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0048] According to this embodiment, a method for preparing an LED bracket with selective plating on the surface of a substrate is provided, comprising the following steps:

[0049] In step A, selective plating, a shield 2 is first prepared according to the electroplating requirements. The shield 2 has a plurality of electroplating holes 21. The shield 2 is attached to the front side of the metal substrate 1 to be electroplated. The metal substrate 1 with the shield 2 attached is then electroplated to form a metal reflective layer at the positions on the front side of the metal substrate 1 corresponding to the electroplating holes 21. After the electroplating is completed, the shield 2 is removed.

[0050] Step B, substrate shaping, is to shape the metal substrate 1 after electroplating in step A by etching or punching, so that the metal substrate 1 is formed with a plurality of grooves and hollow parts that are interconnected.

[0051] Step C, injection molding, injects the metal formed in step B through an injection molding device. After the injection molding material cools and solidifies, the grooves and hollow parts of the metal substrate 1 are filled with the injection molding material and a reflective cup 3 is formed on the front side of the metal substrate 1.

[0052] Step D, debonding, is to debond the surface of the metal substrate 1 after injection molding in step C.

[0053] In step A, if Figure 1 As shown, a rectangular metal substrate 1 is selected. Optionally, the metal substrate 1 is a copper substrate, an iron substrate, or other metal substrates. Then, a shield 2 is prepared according to the electroplating requirements. In this embodiment, the shield 2 is combined with the Figure 2 The shield 2 is rectangular and has a plurality of plating holes 21 arranged in a matrix. The shape and structure of the plating holes 21 can be selectively set according to welding requirements or production requirements. In this embodiment, the plating holes 21 are circular. Figure 3 , a mask 2 is attached to the front side of the metal substrate 1 to be plated. The metal substrate 1 with the mask 2 attached is then electroplated to form a metal reflective layer at the location on the front side of the metal substrate 1 corresponding to the plated holes 21. After the electroplating is completed, the mask 2 is removed. It should be noted that the metal reflective layer can be a metal reflective layer made of gold, silver, copper, nickel, palladium, or the like, or a single metal reflective layer or a combination of two or more metal reflective layers.

[0054] In this embodiment, the shield 2 in step A can be a silicone or film-like structure, and only needs to be able to prevent the covered area of ​​the metal substrate 1 from reacting with the electroplating solution. Specifically, the steps of the electroplating process are as follows: the first step is degreasing, in which the metal substrate 1 covered with the shield 2 is degreased using ultrasound and a degreasing agent; the second step is sulfuric acid neutralization, in which the metal substrate 1 covered with the shield 2 is introduced into a sulfuric acid solution for pickling; the third step is selective electroplating, in which the metal substrate 1 covered with the shield 2 is introduced into an electrolytic solution for electroplating; the fourth step is removing the shield 2 and removing the shield 2 attached to the metal substrate 1; the fifth step is water washing and drying, in which the metal substrate 1 is water washed and dried.

[0055] Compared with the existing technology, the electroplating process is advanced by setting a shield 2 on the front side of the metal substrate 1 that needs to be electroplated. The shield 2 can prevent the surface of the area that does not need to be electroplated from being penetrated by the electroplating solution and being plated with a metal reflective layer. The electroplating area can be controlled more effectively. Compared with the traditional full electroplating method, it can save the use of precious metals, make it easier to recycle the electroplating solution, reduce production costs, and solve the previous problems of precious metal waste and difficulty in recycling in the electroplating solution. The selective plating method can enable the metal substrate 1 to retain a large area that has not been electroplated. The unplated area has a stronger and more firm bond with the injection molding material, ensuring that the LED bracket has good airtightness and greatly improving the reliability of the semiconductor package. The preparation method is reasonably designed and has the characteristics of low overall manufacturing cost and high product quality.

[0056] In step B, if Figure 4 As shown, the metal substrate 1 after electroplating in step A is etched or punched according to the design plan to form an LED bracket substrate, so that the metal substrate 1 is formed with multiple grooves and hollow parts that are interconnected. The specific etching or punching scheme can be designed according to the requirements of the LED bracket substrate.

[0057] like Figure 5 and Figure 7 As shown, in step C, the LED bracket substrate prepared in step B is injection molded. After the injection molding material cools and solidifies, the grooves and hollow portions of the metal substrate 1 are filled with the injection molding material, and a reflector cup 3 is formed on the front side of the metal substrate 1. In step D, the surface of the LED bracket substrate is debonded, completing the entire LED bracket preparation process.

[0058] The LED bracket prepared in this embodiment is as follows: Figures 5 to 7 As shown, an insulating layer 11 is provided on a metal substrate 1. The insulating layer 11 is disposed within a groove and / or hollow portion of the metal substrate 1. A reflector cup 3 is provided on the front side of the metal substrate 1. The reflector cup 3 and the insulating layer 11 are both formed by cooling and solidifying an injection molding material. Specifically, the injection molding material is a thermosetting material, preferably epoxy resin or silicone.

[0059] As a preferred solution, the LED bracket substrate in step B is prepared by etching. Specifically, in step B, the following steps are included:

[0060] Step a, primary dust removal, first perform dust removal on the front and back sides of the electroplated metal substrate 1, specifically through a dust collecting machine, place the metal substrate 1 into the dust collecting machine for dust removal, and the dust collecting machine drives the sticky paper toward the metal substrate 1 so that the dust on the metal substrate 1 adheres to the sticky paper. Optionally, the pressure of the sticky paper of the dust collecting machine is 0.2~0.4Mpa.

[0061] Step b, preheating: the dust-removed metal substrate 1 enters a preheating machine for preheating at a temperature of 90-110° C. The preheating facilitates subsequent bonding with the dry film.

[0062] Step c, attaching the dry film: The preheated metal substrate 1 enters the laminating machine, which applies the dry film to the front and back sides of the metal substrate 1. The laminating machine has a conveying speed of 2.3-3.3 m / min, a temperature of the hot laminating wheel used for laminating the film is 110-120°C, and a pressure of 0.3-0.5 MPa. The temperature of the laminating strip used for cutting is 40-60°C. After the laminating machine completes laminating of each metal substrate 1, it hot presses an indentation area on the dry film (the upper dry film and the lower dry film are pressed together, without the metal substrate 1 between them), so that the indentation area is formed between two adjacent laminating stations of the dry film. The width tolerance of the indentation area is ≤2 mm. The width of the indentation area can be measured with a ruler to determine whether it is within the tolerance range. The indentation area can be observed to determine whether it is flat, clean, and free of bubbles, thereby determining whether the lamination of the dry film and the metal substrate 1 is uniform and whether the lamination quality meets production standards.

[0063] Step d, exposure: After the dry film is attached to the metal substrate 1, partial areas of the dry film on the front and back sides of the metal substrate 1 are exposed to form a pattern on the dry film. Optionally, a secondary dust removal process can be performed before exposure.

[0064] Step e: developing, removing the unexposed areas of the dry film with a developer, wherein the developer is a potassium carbonate solution with a mass concentration of 8 to 14 g / L.

[0065] Step f: one water wash, using pure water to clean the developer remaining on the surface of the dry film.

[0066] Step g, etching, using an etching solution to etch the metal substrate 1 into the hollow portion 12 and the groove 11, the etching solution includes the following components by mass concentration: Cu 2+ The concentration is 120-150 g / L, the hydrochloric acid concentration is 0.7-1.3 mol / L, and the rest is pure water.

[0067] Step h: secondary water washing, using pure water to clean the etching solution remaining on the metal substrate 1.

[0068] Step i: removing the dry film by using a film removal accelerator to remove the dry film on the front and back sides of the metal substrate 1.

[0069] Step j: washing with water three times, using pure water to clean the film removal accelerator remaining on the metal substrate 1.

[0070] Step k, pickling, using pickling solution to clean the residual film removal accelerator, the pickling solution can be 3-5% sulfuric acid, 6-20g / L hydrogen peroxide and Cu2+ One or a combination of two or more micro-etching solutions with a concentration of 5 to 45 g / L. Optionally, the pickling can be performed in two separate pickling steps.

[0071] Step 1: Four water washings: using pure water to clean the pickling solution remaining on the metal substrate 1.

[0072] Step m: drying: drying the metal substrate 1 at a temperature of 80-100° C. to form an LED bracket substrate.

[0073] Preferably, a semi-etching roughening process can be added to step A, as shown in step n, to perform semi-etching roughening on the LED bracket substrate prepared in step m. By roughening the hollowed-out and semi-etched areas, the bonding strength between the epoxy resin and the substrate can be improved, thereby improving the airtightness of the bracket. The roughening process can be carried out using an acidic or alkaline solution. Roughening in this application refers to the formation of etching marks or textures of a certain depth on the material surface. The etching depth and texture type can be controlled by adjusting the concentration, temperature, exposure time, and properties of the etchant itself. After etching is completed, further treatment (such as cleaning, drying, etc.) may be required to remove residual etchant and improve surface quality. It treats the workpiece surface through mechanical or chemical methods to change the morphology and structure of the material surface and increase the surface roughness. The main purpose of this process is to improve the material's friction properties, adhesion, fatigue resistance, and corrosion resistance. Mechanical methods generally include sandblasting and grinding, which use physical effects to produce tiny protrusions and depressions on the material surface, thereby increasing the surface roughness. Chemical methods use chemical reactions to form tiny bumps and shell-like structures on the surface of a material, achieving a roughening effect. For example, you can use acidic or alkaline solutions to chemically etch a metal surface to make it rough.

[0074] Optionally, in step n, the following steps are included:

[0075] Step S1: Cleaning with pure water: Cleaning the LED bracket substrate prepared in step n with pure water.

[0076] Step S2, degreasing, degreasing the LED bracket substrate cleaned in step S1 with sulfuric acid having a concentration of 3-5%.

[0077] Step S3: Super roughening: spray the roughening liquid onto the area of ​​the LED bracket substrate to be roughened. The super roughening temperature is 24-28°C. The Cu content of the roughening liquid is 0.01%. 2+ The concentration is 15-45 g / L, and the micro-etching amount is 0.6-1 μm.

[0078] Step S4, pickling, the pickling solution is hydrochloric acid solution, wherein the concentration of hydrochloric acid is 3-4%, Cu 2+Content ≤2g / L, pickling temperature 80~100℃.

[0079] Step S5: drying: drying the LED bracket substrate at a temperature of 80-100°C.

[0080] Step S6: Water-break test. After acid washing, the LED bracket substrate undergoes a water-break test, with the water-break time ≥ 30 seconds. Specifically, a piece of LED bracket substrate is placed in pure water and then removed vertically. If the entire LED bracket substrate still has water after 30 seconds, it passes. If the water breaks prematurely, it indicates that the board surface is not clean or even greasy. Such workpieces will affect product quality if sent to subsequent processes.

[0081] Although the embodiments disclosed herein are as described above, the contents described herein are merely embodiments for facilitating understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art may make any modifications and variations in the form and details of the embodiments without departing from the spirit and scope of the present invention. However, the scope of patent protection of the present invention shall remain subject to the scope defined by the appended claims.

Claims

1. A method for preparing an LED bracket with selective plating on the surface of a substrate, characterized in that: The following steps are involved: Step A, selective plating, first prepare a mask according to the electroplating requirements, the mask is provided with a plurality of electroplating holes, the mask is attached to the front side of the metal substrate to be electroplated, and then the metal substrate attached with the mask is electroplated, so that a metal reflective layer is formed at the position of the front side of the metal substrate corresponding to the electroplating holes, and the mask is removed after the electroplating is completed; Step B, forming the substrate, forming the metal substrate after electroplating in step A by etching or punching, so that the metal substrate is formed with a plurality of grooves and hollow parts that are interconnected; Step C, injection molding, the metal formed in step B is injection molded by an injection molding device, after the injection molding material is cooled and solidified, the grooves and hollow parts of the metal substrate are filled with the injection molding material and a reflective cup is formed on the front side of the metal substrate; Step D, debonding, debonding the surface of the metal substrate after injection molding in step C.

2. The method for preparing an LED bracket with selective plating on the substrate surface according to claim 1, characterized in that: The mask in step A is a silicone or film structure.

3. The method for preparing an LED bracket with selective plating on the substrate surface according to claim 1 or 2, characterized in that: The metal substrate in step A is a copper substrate or an iron substrate.

4. The method for preparing an LED bracket with selective plating on the substrate surface according to claim 1 or 2, characterized in that: In step B, the LED support substrate is prepared by etching, including the following steps: Step a, primary dust removal, firstly, the front and rear sides of the electroplated metal substrate are dusted, and the metal substrate is placed in a dust collecting machine for dust removal, and the pressure of the dust collecting paper of the dust collecting machine is 0.2-0.4Mpa; Step b, preheating, the dust-removed metal substrate enters a preheating machine for preheating, and the preheating temperature is 90-110°C; Step c, attaching the dry film, the preheated metal substrate enters the laminating machine, and the front and rear sides of the metal substrate are pressed with dry film, the conveying speed of the laminating machine is 2.3-3.3 m / min, the temperature of the hot laminating wheel for laminating is 110-120°C, and the pressure of the hot laminating wheel is 0.3-0.5 MPa, and the temperature of the laminating strip for cutting is 40-60°C; Step d, exposure, after the dry film is attached to the metal substrate, a partial area of ​​the dry film is exposed to form a pattern on the dry film; Step e, developing, removing the unexposed area of ​​the dry film with a developer, the developer being a potassium carbonate solution, and the mass concentration of potassium carbonate being 8 to 14 g / L; Step f, washing once, using pure water to clean the developer remaining on the surface of the dry film; Step g, etching, using an etching solution to etch the metal substrate into hollow parts and grooves, the etching solution comprising the following components in mass concentration: Cu 2+ The concentration is 120-150 g / L, the hydrochloric acid concentration is 0.7-1.3 mol / L, and the rest is pure water; Step h, secondary water washing, using pure water to clean the etching solution remaining on the metal substrate; Step i, removing the dry film, using a film removal accelerator to remove the dry film on the front and back sides of the metal substrate; Step j, washing three times with water, using pure water to clean the film removal accelerator remaining on the metal substrate; Step k, pickling, using a pickling solution to clean the residual film removal accelerator, the pickling solution is 3-5% sulfuric acid, 6-20g / L hydrogen peroxide and Cu 2+ One or a combination of two or more micro-etching solutions with a concentration of 5 to 45 g / L; Step 1, washing four times with water, using pure water to clean the acid wash solution remaining on the metal substrate; Step m: drying: drying the metal substrate at a temperature of 80 to 100° C. to form an LED bracket substrate.

5. The method for preparing an LED bracket with selective plating on the substrate surface according to claim 4, characterized in that: The method further comprises the step n of performing a semi-etching roughening treatment on the LED bracket substrate prepared in the step m; In step n, the following steps are included: Step S1, pure water cleaning, using pure water to clean the LED bracket substrate prepared in step n; Step S2, degreasing, degreasing the LED bracket substrate cleaned in step S1 with sulfuric acid having a concentration of 3 to 5%; Step S3, super roughening, spraying the roughening liquid onto the area of ​​the LED bracket substrate to be roughened, the super roughening temperature is 24-28°C, and the Cu 2+ The concentration is 15-45 g / L, and the micro-etching amount is 0.6-1 μm; Step S4, pickling, the pickling solution is a hydrochloric acid solution, wherein the concentration of hydrochloric acid is 3-4%, Cu 2+ Content ≤2g / L, pickling temperature 80~100℃; Step S5, drying, drying the LED bracket substrate at a drying temperature of 80-100° C.; Step S6, water break test, the LED bracket base after acid washing is subjected to water break test, and the water hanging time is ≥30s.

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