CN111326640A - Method for forming window on light-emitting diode carrier plate - Google Patents

Abstract

The invention provides a method for forming a window on a light-emitting diode carrier plate, which comprises the following steps: forming a circuit layer and a solder mask layer on a substrate, wherein the circuit layer is provided with a working surface, and the solder mask layer covers the working surface of the circuit layer; and forming a plurality of windows on the solder mask layer by a laser engraving machine, so that the working surface of the circuit layer is not covered by the solder mask layer in the windows. Therefore, the window wall of the window has good smoothness and the problem of over-etching can be solved.

Description

Method for forming a window on a light-emitting diode substrate

technical field

The present invention relates to a method for manufacturing a circuit board, in particular to a method for manufacturing a light-emitting diode substrate with a window area.

Background technique

The traditional circuit board structure usually forms a solder mask on the metal circuit layer to cover the circuits and metal surfaces that do not need to be soldered, so as to prevent short circuits during soldering and save the amount of solder; on the other hand, the solder mask It can prevent water vapor and electrolyte from entering the circuit board, avoid the oxidation of the circuit layer and damage the electrical properties, and also prevent the device from damaging the circuit layer; Solder layers also provide insulation between adjacent circuits.

Next, using a development and etching process, the solder resist layer on the designated solder joints of the circuit layer is removed, so that the circuit layer of the solder joints is exposed, so as to facilitate the subsequent soldering process. The development and etching process is to use UV light or visible light of a specific wavelength band to irradiate the solder mask to cure the solder mask; then use a special chemical solvent to remove the uncured solder mask material to make the solder joints The circuit layers are exposed. However, when the solder mask is cured by light, because the reflectivity and thickness of the solder mask itself affect the penetration of UV light or visible light, the solder mask material at the bottom of the solder mask is not fully cured and is removed by special chemical solvents. . In this way, the problem of overcut is likely to occur in the developing process, resulting in the exposed circuit layer that should be protected by the solder mask. When the subsequent soldering process is performed, it is likely to cause a short circuit or even damage the circuit board.

SUMMARY OF THE INVENTION

In view of this, the main object of the present invention is to provide a light-emitting diode substrate manufacturing process, which can accurately expose a predetermined exposed circuit layer.

In order to achieve the above object, the present invention provides a method for forming a window on a light-emitting diode carrier (hereinafter referred to as an LED carrier), comprising: forming a circuit layer and a solder resist layer on a substrate, and the circuit layer has a working The solder mask covers the working surface of the circuit layer; and a laser engraving machine is used to form a plurality of openings on the solder mask, so that the working surface of the circuit layer is not covered by the solder mask in the openings.

The window of the solder mask formed by laser engraving has good flatness of the window wall, which can greatly improve the problem of easy over-etching in the prior art development process; The window is opened by the exposure and development process, so the selected solder mask material can be selected without adding a photoinitiator, which can further reduce the material cost of the solder mask layer.

The details of other functions and embodiments of the present invention are described as follows with reference to the drawings.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that are used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments described in this application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

1 to 4 are schematic cross-sectional views of the manufacturing process of the first embodiment of the present invention;

5 is a schematic cross-sectional view of an LED substrate fabricated by a process according to a second embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view of an LED substrate fabricated by a manufacturing process according to a third embodiment of the present invention.

Symbol Description

10 substrates 20 circuit layers

21 working surface 22 surface coating

30 Solder mask 31 Window

32 window wall 40LED die

Detailed ways

The positional relationships described in the following embodiments, including: up, down, left and right, are based on the directions shown by the components in the drawings unless otherwise specified.

The LED carrier of the present invention can be a single-layer board structure or a multi-layer composite board structure, which can be a carrier board for a flexible printed circuit (FPC) or a carrier for a rigid circuit board (Printed Circuit Board, PCB). , the material used may be, but not limited to, polyethylene terephthalate (PET) or other polyester films, polyimide films, polyamideimide films, polypropylene films, and polystyrene films.

Referring to FIG. 1 , in the first embodiment of the present invention, a circuit layer 20 having a working surface 21 is first formed on a substrate 10 . For example, a thin copper foil can be formed on the substrate 10 Copper is plated to form a copper conductive layer, and then the copper conductive layer is imaged by the circuit image transfer technology to form the circuit layer 20 as described above.

Next, as shown in FIG. 2 , a solder resist layer 30 is formed on the substrate 10 so that the solder resist layer 30 covers the working surface 21 of the circuit layer 20 . In a possible embodiment, the solder resist layer 30 is coated on the substrate 10 by, for example, screen printing, and then hardened. In other possible embodiments, the solder resist layer 30 is formed by, for example, laminating a semi-cured solder resist dry film on the substrate 10 and then hardening it. In a possible embodiment, the material of the solder resist layer is mainly composed of thermosetting resin, light curing resin or a mixture of the two. In a possible embodiment, the composition of the solder resist layer does not contain a photoinitiator or a photocuring agent.

Next, as shown in FIG. 3 , a laser engraving machine is used to form a plurality of openings 31 on the solder resist layer 30 (only one is shown in the drawing as a representative), so that the working surface 21 of the circuit layer 20 is in the opening 31 is not covered by the solder mask layer 30. In particular, the formation of the window opening of the present invention does not involve exposure and development processes. The solder resist layer 30 has a plurality of window walls 32 respectively defining the windows 31 , and at least a part of the window walls 32 is perpendicular to the working surface 21 .

As shown in FIG. 4 , in the subsequent LED packaging process, a surface plating layer 22 can be formed on the working surface 21 of the circuit layer 20 , which can be but not limited to one of a nickel layer, a gold layer, a silver layer, a palladium layer or Its laminated structure, such as electroplated nickel-gold laminated structure, electroplated nickel-silver-gold laminated structure, electroplated nickel-silver laminated structure, electroless nickel-gold laminated structure, electroless nickel-silver laminated structure or nickel-palladium-gold laminated structure. Then, the LED die 40 is mounted on the surface plating layer 22 in the opening 31. Solder or conductive glue can also be formed on the surface plating layer 22 before mounting to increase the mounting yield. However, it is not particularly drawn in the drawings. Show. The applicable LED dies can be flip-chip LED dies, vertical LED dies or horizontal LED dies. If necessary, the poles of the LED die can be connected to the circuit layer 20 with wires through wire bonding technology. The electrical contacts form electrical connections. Preferably, the top surface of the solder mask layer 30 is higher than the LED die accommodated in the opening 31 .

Referring to FIG. 5 , the manufacturing process of the LED substrate according to the second embodiment of the present invention is substantially the same as that of the first embodiment. That is, the window 31 is a tapered window, so that the light emitted by the LED die is converged to avoid astigmatism. Preferably, the solder resist layer 30 has a lower reflection for the light wave emitted by the LED die. ratio, such as a reflectance of less than 50%.

Referring to FIG. 6 , the manufacturing process of the LED substrate according to the third embodiment of the present invention is substantially the same as that of the first embodiment. That is, the window 31 is a gradually expanding window, so that the light emitted by the LED die can be reflected by the window wall 32 to improve the brightness. Preferably, the solder mask layer 30 has a higher level of light waves emitted by the LED die. reflectivity, such as higher than 85%.

In view of the above, the solder resist layer formed by laser engraving in the present invention has good flatness of the window wall, which can greatly improve the problem of easy over-etching in the development process of the prior art; in addition, the present invention also produces unexpected effects. In this case, since the exposure and development process does not need to be used to open the window, the selected solder mask material can be in a formulation without adding a photo initiator, thereby further reducing the material cost of the solder mask layer. In other words, the process disclosed in the present invention can reduce the material cost while improving the machining accuracy, which can indeed meet the needs of the industry.

The above-mentioned embodiments and/or implementations are only used to illustrate the preferred embodiments and/or implementations for realizing the technology of the present invention, and are not intended to limit the implementation of the technology of the present invention in any form. Personnel, without departing from the scope of the technical means disclosed in the content of the present invention, may make some changes or modifications to other equivalent embodiments, but they should still be regarded as substantially the same technology or embodiment of the present invention.

Claims (5)

1. A method for forming a window on a light-emitting diode carrier, comprising: A circuit layer and a solder resist layer are formed on a substrate, the circuit layer has a working surface, and the solder resist layer covers the working surface of the circuit layer; and A plurality of openings are formed on the solder mask by a laser engraving machine, so that the working surface of the circuit layer is not covered by the solder mask in the openings. 2 . The method of claim 1 , wherein the solder mask layer has a plurality of window walls respectively defining the windows, and at least a part of the window walls are vertical. 3 . on this work surface. 3 . The method of claim 1 , wherein the solder mask layer has a plurality of window walls respectively defining the windows, and at least a part of the window walls are connected with the window walls. 4 . An acute angle is formed between the working surfaces within the corresponding window opening range. 4 . The method of claim 1 , wherein the solder mask layer has a plurality of window walls respectively defining the windows, and at least a part of the window walls are connected with the window walls. 5 . An obtuse angle is formed between the working surfaces within the corresponding window opening range. 5 . The method of claim 1 , wherein at least a part of the opening is for accommodating at least one LED die, and the top surface of the solder mask is higher than the capacitance 5 . LED dies placed in the openings.

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