Circuit board with double layers of ink and circuit assembly

Abstract

The utility model relates to a circuit board with double-layer ink and a circuit assembly. The circuit board with the double-layer ink comprises a glass substrate, and a circuit layer, a first ink layer and a second ink layer which are sequentially arranged on the glass substrate from bottom to top, the first ink layer and the second ink layer are provided with windows at the position of a chip bonding pad in the circuit layer, and a second window on the second ink layer is larger than a first window on the first ink layer, so that the inner sides of the first window and the second window form step levels; according to the utility model, the step windowing design is carried out at the solder resist windowing position, thereby effectively avoiding the cold solder joint risk caused by uncontrollable burrs at the edge of the single-layer thick ink windowing during the packaging of the LED chip, effectively avoiding the short circuit risk caused by uncontrollable tin amount of solder paste during the packaging of the LED chip, and achieving the better welding and packaging of the LED chip.

Description

Technical Field

[0001] The utility model relates to the field of circuit boards, in particular to a double-layer ink circuit board and a circuit component. Background Art

[0002] Fabricating a circuit board on a glass substrate and then encapsulating the LED chip, thus integrating the circuit board and display, has been adopted in high-end LED displays. However, due to the extremely small solder pad openings on LED glass substrates (effective pad size of 0.2 x 0.2 mm), the solder mask openings are 0.1 mm larger on each side than the pad openings. This can lead to short circuits between pads during SMT chip encapsulation. If the solder mask ink is designed with a pressed-pad design, the ink will shift to the side of the openings, occupying the effective pad size, ultimately preventing effective soldering and encapsulation of the LED chip. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a double-layer ink circuit board and a circuit component to achieve better welding and packaging of LED chips.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A double-layer ink circuit board comprises a glass substrate, and a circuit layer, a first ink layer and a second ink layer arranged on the glass substrate in order from bottom to top;

[0006] The first ink layer and the second ink layer are provided with windows at the position of the chip pad in the circuit layer, and the second window on the second ink layer is larger than the first window on the first ink layer, so that the inner sides of the first window and the second window form a stepped layer.

[0007] Furthermore, the sum of the thicknesses of the first ink layer and the second ink layer is less than 30 μm.

[0008] Furthermore, the thickness of the first ink layer is less than 15 μm.

[0009] Furthermore, the thickness of the second ink layer is less than 15 μm.

[0010] Furthermore, the width of the first window is greater than the width of the pad.

[0011] Furthermore, the width of the first window is 0.03 mm greater than the width of the pad.

[0012] Furthermore, the width of the second window is greater than the width of the pad.

[0013] Furthermore, the width of the second window is 0.1 mm greater than the width of the pad.

[0014] Furthermore, the first ink layer and the second ink layer are both highly reflective white oil.

[0015] In order to solve the above technical problems, another technical solution adopted by the present invention is:

[0016] A circuit assembly includes a circuit board and an LED chip;

[0017] The circuit board is the double-layer ink circuit board described above;

[0018] The LED chip is electrically connected to the chip pad on the circuit board through SMT mounting.

[0019] The beneficial effects of the present invention are as follows: a double-layer ink circuit board and circuit assembly of the present invention has a stepped window design at the solder mask window position, which effectively avoids the risk of cold soldering when LED chips are packaged due to uncontrollable burrs on the edges of single-layer thick ink windows, and effectively avoids the risk of short circuit caused by uncontrollable tin amount under solder paste when LED chips are packaged, thereby achieving better welding and packaging of LED chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an example cross-sectional view of a double-layer ink circuit board according to an embodiment of the present utility model;

[0021] Figure 2 This is a top view of an example of the window position of a double-layer ink circuit board according to an embodiment of the present utility model;

[0022] Figure 3 This is an example diagram of the solder paste printing position of a double-layer ink circuit board according to an embodiment of the present utility model;

[0023] Description of labels:

[0024] 1. Glass substrate; 2. Circuit layer; 3. First ink layer; 4. Second ink layer; 5. Chip pad; 6. Solder paste. DETAILED DESCRIPTION

[0025] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following description is given in conjunction with the embodiments and the accompanying drawings.

[0026] Please refer to Figure 1 as well as Figure 2 , a double-layer ink circuit board, comprising a glass substrate, and a circuit layer, a first ink layer, and a second ink layer sequentially arranged from bottom to top on the glass substrate;

[0027] The first ink layer and the second ink layer are provided with windows at the position of the chip pad in the circuit layer, and the second window on the second ink layer is larger than the first window on the first ink layer, so that the inner sides of the first window and the second window form a stepped layer.

[0028] From the above description, it can be seen that the beneficial effects of the present invention are: a double-layer ink circuit board and circuit assembly of the present invention has a stepped window design at the solder mask window position, which effectively avoids the risk of cold soldering when LED chips are packaged due to uncontrollable burrs on the edges of single-layer thick ink windows, and at the same time effectively avoids the risk of short circuit caused by uncontrollable amount of tin in the solder paste when LED chips are packaged, thereby achieving better welding and packaging of LED chips.

[0029] Furthermore, further, the sum of the thicknesses of the first ink layer and the second ink layer is less than 30 μm.

[0030] From the above description, it can be seen that the thickness of the two layers of ink is controlled to be within 30μm, which effectively avoids the risk of the chip welding size being reduced due to the large burrs on the edge of the window when the thickness of the single layer of ink is 30μm.

[0031] Furthermore, the thickness of the first ink layer is less than 15 μm.

[0032] Furthermore, the thickness of the second ink layer is less than 15 μm.

[0033] As can be seen from the above description, the thickness of the first ink layer and the second ink layer are both less than 15 μm, which simply and effectively realizes the control of the stacking thickness of the two ink layers.

[0034] Furthermore, the width of the first window is greater than the width of the pad.

[0035] Furthermore, the width of the first window is 0.03 mm greater than the width of the pad.

[0036] Furthermore, the width of the second window is greater than the width of the pad.

[0037] Furthermore, the width of the second window is 0.1 mm greater than the width of the pad.

[0038] From the above description, it can be seen that the width of the first window is 0.03 mm greater than the width of the pad, and the width of the second window is 0.1 mm greater than the width of the pad, realizing a stepped window design.

[0039] Furthermore, the first ink layer and the second ink layer are both highly reflective white oil.

[0040] As can be seen from the above description, the solder resist ink used is high-reflective white oil as a specific embodiment of the present invention.

[0041] A circuit assembly includes a circuit board and an LED chip;

[0042] The circuit board is the double-layer ink circuit board described above;

[0043] The LED chip is electrically connected to the chip pad on the circuit board through SMT mounting.

[0044] The utility model discloses a double-layer ink circuit board and a circuit component, which are suitable for LED chip packaging using the SMT process.

[0045] Please refer to Figure 1 and Figure 2 , the first embodiment of the present utility model is:

[0046] A double-layer ink circuit board comprises a glass substrate 1, and a circuit layer 2, a first ink layer 3, and a second ink layer 4 arranged on the glass substrate 1 in order from bottom to top;

[0047] The first ink layer 3 and the second ink layer 4 are provided with windows at the position of the chip pad 5 in the circuit layer 2. The second window on the second ink layer 4 is larger than the first window on the first ink layer 3, so that the inner sides of the first window and the second window form a stepped layer.

[0048] The sum of the thicknesses of the first ink layer 3 and the second ink layer 4 is less than 30 μm.

[0049] The choice and thickness of ink vary according to product requirements. In this embodiment, the first ink layer 3 and the second ink layer 4 are both highly reflective white ink.

[0050] In this embodiment, the thickness of the first ink layer 3 is less than 15 μm, which effectively controls the irregularities of the ink burrs on the sides of the ink window, occupies the effective size of the pad, and avoids the risk of LED chip welding falling off.

[0051] The thickness of the second ink layer 4 is less than 15 μm, so that the thickness of the two layers of ink is controlled to be within 30 μm, effectively avoiding the risk of the chip soldering size being reduced due to excessive burrs on the edge of the window when the thickness of the single layer of ink is 30 μm.

[0052] The width of the first window is greater than the width of the pad. The width of the first window is greater than the width of the pad by 0.03 mm.

[0053] The width of the second window is greater than the width of the pad. The width of the second window is greater than the width of the pad by 0.1 mm.

[0054] In this embodiment, the large window is designed to be 0.1mm larger on one side of the pad, and the small window is designed to be 0.03mm larger on one side. The first layer of ink outside the small window is used to block the problem of excessive tin amount when SMT printing solder paste 6, effectively avoiding the occurrence of tin short circuit when the LED chip is mounted.

[0055] The manufacturing steps of the double-layer ink circuit board are as follows:

[0056] Step 1: Follow the normal single-panel circuit production process to complete the process from feeding - copper plating - circuit production - AOI scanning - sandblasting cleaning.

[0057] Step 2: Ink printing, complete the production process in sequence according to the single-sided double-layer ink: use a 120T screen to print a layer of high-reflective white oil (ink thickness ≤ 15μm) on the entire plate - pre-curing - exposure (the film window size is designed to be 30μm larger than the single side of the pad) - development - curing - sandblasting cleaning - print a second layer of high-reflective white oil on the first layer of ink (ink thickness ≤ 15μm) - pre-curing - exposure (the film window size is designed to be 0.1mm larger than the single side of the pad) - development - curing.

[0058] Step 3: Complete the subsequent process of the single-sided glass carrier normally.

[0059] The second embodiment of the present invention is:

[0060] A circuit assembly includes a circuit board and an LED chip;

[0061] The circuit board is the double-layer ink circuit board described above;

[0062] The LED chip is electrically connected to the chip pad 5 on the circuit board through SMT mounting.

[0063] LED chip packaging process: solder paste printing (the steel mesh window size is designed according to the small window size of the first layer) - LED chip placement - LED chip welding - quality inspection - packaging and shipment.

[0064] Please refer to Figure 3 , solder paste 6 is printed on the pad of circuit layer 2.

[0065] In summary, the present invention provides a double-layer ink circuit board and circuit assembly. Without reducing the effective soldering area of ​​the pads, the invention utilizes a single layer of solder mask ink with a thickness of ≤15μm at a small window to prevent solder paste from flowing into non-pad areas. This effectively controls the amount of solder paste printed, preventing short circuits caused by excessive solder paste when the pads pass through the non-pad areas during LED chip placement. Furthermore, because the ink thickness at the small window is ≤15μm, irregular burrs along the edges of the window are effectively controlled, which can take up the effective pad size and mitigate the risk of LED chip soldering failure. The present invention utilizes a larger window (0.1mm larger than a single edge of the pad), controlling the thickness of the outer layer to ≤15μm and the thickness of both layers to within 30μm. This effectively mitigates the risk of chip soldering dimensions being reduced due to excessive burrs along the window edges when a single layer of ink is stacked at 30μm.

[0066] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A double-layer ink circuit board, characterized in that: The invention comprises a glass substrate, and a circuit layer, a first ink layer and a second ink layer sequentially arranged on the glass substrate from bottom to top; The first ink layer and the second ink layer are provided with windows at the position of the chip pad in the circuit layer, and the second window on the second ink layer is larger than the first window on the first ink layer, so that the inner sides of the first window and the second window form a stepped layer.

2. A double-layer ink circuit board according to claim 1, characterized in that: The sum of the thicknesses of the first ink layer and the second ink layer is less than 30 μm.

3. A double-layer ink circuit board according to claim 2, characterized in that: The thickness of the first ink layer is less than 15 μm.

4. A double-layer ink circuit board according to claim 2, characterized in that: The thickness of the second ink layer is less than 15 μm.

5. The double-layer ink circuit board according to claim 1, characterized in that: The width of the first window is greater than the width of the pad.

6. The double-layer ink circuit board according to claim 5, characterized in that: The width of the first window is 0.03 mm greater than the width of the pad.

7. The double-layer ink circuit board according to claim 1, characterized in that: The width of the second window is greater than the width of the pad.

8. The double-layer ink circuit board according to claim 7, characterized in that: The width of the second window is 0.1 mm greater than the width of the pad.

9. The double-layer ink circuit board according to claim 1, characterized in that: The first ink layer and the second ink layer are both highly reflective white oil.

10. A circuit assembly, characterized in that: Including circuit boards and LED chips; The circuit board is a double-layer ink circuit board as described in any one of claims 1 to 6 above; The LED chip is electrically connected to the chip pad on the circuit board through SMT mounting.

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