TWI681572B - High covering rate led carrier board - Google Patents

Abstract

A high covering rate LED carrier board includes a substrate. The substrate has multiple LED carrier strips oriented along a first direction. A slot is defined between every two adjacent and parallel LED carrier strips. Each LED carrier strip has a LED carrying surface for LED chip to be mounted thereon. The LED carrying surface has multiple LED carrier sections arranged along the first direction. Each LED carrier section has a metallic conductor. The substrate further has a solder resist layer partially coverring the metallic conductor on each LED carrier section at a covering rate of more than 50%.

Description

High coverage LED carrier board

The invention relates to a light emitting diode carrier board, in particular to a surface adhesive type light emitting diode (SMD LED) carrier board.

The process of light emitting diode (hereinafter referred to as LED) can be divided into upstream epitaxial manufacturing, midstream chip manufacturing, and downstream packaging testing and system assembly. After the LED chip is manufactured, the LED chip is adhered to the light emitting diode. On the board (hereinafter referred to as LED carrier board), after a series of manufacturing processes such as solid crystal, curing, wire bonding, sealing, cutting, etc., a light-emitting diode element (hereinafter referred to as LED element) is made.

The existing LED carrier board is shown in FIGS. 1A and 8B of the I464928 patent, for example. The solid crystal surface 11F of the substrate 11 has terminal electrodes 13A and 13B. Each terminal electrode has a functional portion 133 for electrically connecting the chip and the wire bonding wire. For solder resist or other purposes, a solder mask layer 14 is also formed on the substrate 11, that is, the solder mask layer 14 only covers a small part of the surface of the terminal electrodes 13A, 13B, and the remaining circuit structure not covered by the solder mask layer 14 (Including components 131, 132, 133) are surface-treated and plated with gold, silver, nickel or their alloys.

However, the existing LED carrier board has its shortcomings: (1) the surface treatment area is large, the uniformity of the plating layer is not easy to control, and the cost is high; (2) due to the uneven thickness of the plating layer, the subsequent process is likely to cause overflow glue; (3) Dispensing on the metal surface is very easy to cause the diffusion of glue gas; (4) The combination of silver glue and insulating glue and metal plating is poor.

In view of this, the main object of the present invention is to provide an LED carrier board that can reduce the cost of surface treatment.

In order to achieve the above object, the present invention provides a high-coverage LED carrier board, which includes a substrate having a light-emitting diode carrier surface (hereinafter referred to as LED carrier surface) for mounting a plurality of light-emitting diode chips, each The LED bearing surface has a plurality of LED bearing areas, and each LED bearing area has a metal conductor; wherein, the substrate further has a solder mask, which partially covers the metal conductor of each LED bearing area, and the solder mask covers the metal conductor The rate is greater than 50%.

Based on the above design, less than 50% of the metal conductors on the LED bearing surface are left exposed. The cost of surface treatment for subsequent electroplating and electroless plating can be significantly reduced, and it can help improve the thickness uniformity of the LED carrier board.

11‧‧‧LED Carrying Bar

12‧‧‧Slotted

13‧‧‧LED bearing surface

14‧‧‧LED bearing area

141‧‧‧Non-metallic conductor area

15‧‧‧Metal conductor

16‧‧‧Soldering layer

161‧‧‧Open the window

17‧‧‧Surface coating

20‧‧‧LED chip

30‧‧‧Wire

D‧‧‧First direction

Figure 1 is a top view of one embodiment of a high-coverage LED carrier board.

Figure 2 is an enlarged schematic view of one embodiment of a high-coverage LED carrier board, where the dotted line portion represents the outline of the metal conductor covered by the solder mask, and the one-by-one chain portion represents the range of the LED bearing area.

Figures 3 to 5 are schematic diagrams of the manufacturing process of one embodiment of the high-coverage LED carrier board.

FIG. 6 is an enlarged schematic view of an embodiment of a high-coverage LED carrier board carrying an LED chip.

FIG. 7 is an enlarged schematic view of another embodiment of a high-coverage LED carrier board carrying LED chips.

Please refer to Figures 1 and 2, in one of the embodiments, the high-coverage LED carrier board includes a A substrate, the substrate has a plurality of LED carrying bars 11 extending in the first direction D, a slot 12 is provided between any two adjacent and parallel LED carrying bars 11, each LED carrying bar has one for carrying a plurality of LED chips Each of the LED bearing surfaces 13 has a plurality of LED bearing regions 14 arranged along the first direction D. The edges of the LED bearing regions 14 are indicated by dotted chain lines in FIG. The chain line is also a cutting line in the subsequent slitting process. Each LED bearing area 14 has a metal conductor 15 and a non-metal conductor area 141. The substrate itself has one or more insulating layers and one or more circuit layers. These insulating layers are, for example, epoxy resin, woven glass, polyester or other materials commonly used to make circuit board substrates. The circuit layer includes The aforementioned metal conductor 15 electrically connected to the LED chip and the circuit structure on other surfaces. The high-coverage LED carrier board can be applied to the packaging process of SMD LED elements, for example.

The substrate further has a solder resist layer 16 and a surface plating layer 17, the solder resist layer 16 partially covers the metal conductors 15 of each LED bearing area 14, and completely covers the non-metallic conductor areas 141, so that the thickness uniformity throughout the substrate is greatly improved. To avoid the problem of glue overflow in the subsequent process due to uneven thickness.

The metal conductor 15 next to the slot 12 may not be covered by the solder mask 16, but the coverage of the metal mask by the solder mask 16 is greater than 50%, preferably greater than 60%, and more preferably greater than 70% to improve the substrate Uniform thickness throughout.

As shown in FIGS. 3 to 5, the metal conductor 15 is first formed on the LED bearing area 14 and patterned, and then the solder mask 16 is formed on the LED bearing surface 13 and covers the metal conductor 15 and the non-metallic conductor area 141, Then, a window opening 161 is formed at the electrical contact 151 that needs to be electrically connected to the LED chip, and finally a surface plating layer 17 is formed on the surface of the electrical contact 151 in the window 161 by electroplating or electroless plating. Among them, the area ratio of the openings 161 to the solder mask 16 is less than 20%, preferably less than 10%, and more preferably less than 5%, thereby reducing the cost of surface treatment.

Please refer to FIG. 6, in a possible implementation manner, the aforementioned high-coverage LED carrier board In the continuous process, the LED chip 20 is mounted by surface mounting technology, and the two poles of the LED chip 20 are electrically connected to the electrical contacts 151 in the window 161 by wires 30 by wire bonding technology. The aforementioned surface plating layer 17 is formed. In this embodiment, the LED chip 20 is a horizontal type chip, and is electrically connected to two electrical contacts 151 through two wires 30. Among them, the area of each window 161 is 2-10 times the cross-sectional area of the wire 30, preferably 2-8 times, if the multiple is less than 2 times, it may be difficult to realize the wire 30 and the electrical contact 151 by wire bonding technology If the multiple of the electrical connection is greater than 10 times, it will increase the invalid area of the window 161 that is not electrically connected to the wire 30, and increase the cost of surface treatment.

Please refer to FIG. 7, in another possible embodiment, the LED chip 20 is a vertical chip and is electrically connected to one of the electrical contacts 151 through a wire 30, and the other electrical contact 151 is located on the LED chip 20 The electrodes on the bottom are electrically connected.

In a possible embodiment, one LED carrying area 14 is formed with three windows 161, so that the LED carrying area 14 can be applied to both horizontal LED chips and vertical LED chips.

In the aforementioned embodiment, a plurality of slots are formed on the substrate. In other possible implementations, the substrate may not be formed with slots; in a possible implementation, the substrate is formed with a plurality of via holes corresponding to the LED bearing regions, respectively.

Through the above technology, less than 50% of the metal conductors on the LED bearing surface in this creation are exposed to the outside. The cost of surface treatment for subsequent electroplating and electroless plating can be significantly reduced, and it can help to improve the thickness uniformity of the LED carrier board. .

11‧‧‧LED Carrying Bar

12‧‧‧Slotted

13‧‧‧LED bearing surface

14‧‧‧LED bearing area

141‧‧‧Non-metallic conductor area

15‧‧‧Metal conductor

16‧‧‧Soldering layer

161‧‧‧Open the window

D‧‧‧First direction

Claims (8)

A high-coverage light-emitting diode carrier board includes: a substrate having a light-emitting diode bearing surface for mounting a plurality of light-emitting diode chips, the light-emitting diode bearing surface having a plurality of light-emitting diodes bearing Each of the light-emitting diode carrying regions has a metal conductor; wherein, the substrate further has a solder mask, the solder mask partially covering the metal conductors of each of the light-emitting diode carrying zones, the solder mask against the metal The coverage of the conductor is greater than 50%; the substrate has a plurality of light-emitting diode carrying bars extending in a first direction, and there is a slot between any two adjacent and parallel light-emitting diode carrying bars The light-emitting diode carrying bar has the light-emitting diode carrying surface. The high-coverage light-emitting diode carrier board according to claim 1, wherein the coverage of the solder mask on the metal conductor is greater than 60%. The high-coverage light-emitting diode carrier board according to claim 1, wherein the metal conductor includes at least one pair of electrical contacts for electrically connecting at least one of the light-emitting diode chips, and the solder mask has a number of The openings covering the electrical contacts are less than 20% of the area of the solder mask. The high-coverage light-emitting diode carrier board according to claim 1, wherein the metal conductor includes at least one pair of electrical contacts for electrically connecting at least one of the light-emitting diode chips, and the solder mask has a number of The openings covering the electrical contacts, the openings occupying less than 10% of the area of the solder mask. The high-coverage light-emitting diode carrier board according to claim 1, wherein the metal conductor includes at least one pair of electrical contacts for at least one of the light-emitting diode chips to be electrically connected through at least one wire. The solder layer has a number of openings that do not cover the electrical contacts, and the area of each opening is 2-10 times the cross-sectional area of the wire. The high-coverage light-emitting diode carrier board according to claim 1, wherein the metal conductor includes at least one pair of electrical contacts for at least one of the light-emitting diode chips to be electrically connected through at least one wire. The solder layer has a number of openings that do not cover the electrical contacts, and the area of each opening is 2-8 times the cross-sectional area of the wire. The high-coverage light-emitting diode carrier according to any one of claims 3 to 6, wherein the substrate further includes a plurality of surface plating layers formed on the electrical contact surfaces in the openings, respectively . The high-coverage light-emitting diode carrier board according to claim 1, wherein each of the light-emitting diode carrier regions has a non-metallic conductor region, and the solder resist layer more completely covers the non-metallic conductor region.

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