Lamp bead structure and display screen

Abstract

The utility model discloses a lamp bead structure and a display screen, and relates to the technical field of chip packaging. The bonding pad is connected with the substrate, and a thinning structure is arranged on the bonding pad; the solder paste is arranged on the surface of the bonding pad, and the solder paste is arranged in the thinning structure; and the light-emitting chip is connected with the bonding pad through solder paste, and the light-emitting chip is arranged on the thinning structure. According to the invention, the thinning structure is arranged on the bonding pad main body to accommodate flowing solder paste, so that a light-emitting chip can be conveniently connected with the bonding pad through the solder paste.

Description

Technical Field

[0001] The utility model relates to the technical field of chip packaging, in particular to a lamp bead structure and a display screen. Background Art

[0002] Flip-chip packaging is an advanced semiconductor packaging technology that uses bumps on the chip to directly interconnect components face-down to a substrate, carrier, or circuit board. Compared to traditional packaging methods, this technology offers smaller size, thinner thickness, lighter weight, higher I / O density, and better electrical performance. It also boasts high luminous efficiency, excellent heat dissipation, high current density capability, excellent stability, strong ESD resistance, and the elimination of wirebonds.

[0003] When packaging existing chips, solder paste is needed to connect the chip to the pad.

[0004] For example, Chinese patent publication number CN118073338A discloses a fine-pitch, high-brightness display device comprising: a substrate, the substrate being divided into a front side and a back side; a plurality of upper core regions disposed on the front side of the substrate; a plurality of solder pads disposed on the back side of the substrate; a light-emitting chip secured within the upper core region by solder paste and electrically connected to the substrate; a plastic package encapsulating the front side of the substrate for sealing and protecting the light-emitting chip; solder resist ink is applied to both the front and back sides of the substrate, excluding the upper core region and the solder pads; and direction marking ink is also applied to the back side of the substrate. By reducing the number of chips and using dual-G light, controlled by software and programs, the display effect is comparable to that of conventional display devices, effectively saving costs.

[0005] However, current solder paste soldering performance is poor. For example, if the volume of solder paste is too small during printing, the surface of the normal pad will turn gray or black after reflow, and less solder paste will accumulate at the bottom of the chip, resulting in almost no bonding between the chip and the pad, and low product reliability. If the volume of solder paste is too large, the surface of the normal pad will have a large curvature after reflow, tilting the top of the chip and affecting the consistency of the light emitting angle.

[0006] Therefore, it is urgent to develop a lamp bead structure and a display screen to solve the problems in the prior art. Summary of the Invention

[0007] The purpose of the present utility model is to provide a lamp bead structure and a display screen, which solves the problem of poor soldering effect of solder paste due to excessive or insufficient amount of solder paste during solder paste printing proposed in the above-mentioned background technology by providing a thinning structure at the position of the solder pad body to be connected to the light-emitting chip to accommodate solder paste.

[0008] To achieve the above purpose, the present invention provides the following technical solutions:

[0009] A lamp bead structure, comprising:

[0010] substrate;

[0011] a soldering pad connected to the substrate, wherein a thinning structure is provided on the soldering pad;

[0012] Solder paste, the solder paste being disposed on the surface of the solder pad and the solder paste being disposed in the thinning structure;

[0013] A light-emitting chip is connected to the pad via solder paste, and the light-emitting chip is arranged on the thinned structure.

[0014] Furthermore, the height of the thinned structure is 3 μm-7 μm.

[0015] Furthermore, the edge of the thinning structure is provided with a transition slope.

[0016] Furthermore, the length of the transition slope is 5 μm-10 μm.

[0017] Furthermore, the thinning structure is an etched structure.

[0018] Furthermore, the length of the thinning structure is greater than the length of the light-emitting chip, and the width of the thinning structure is greater than the width of the light-emitting chip.

[0019] Furthermore, it also includes a solder resist, which is arranged on the surface of the pad.

[0020] Furthermore, the substrate is a resin substrate.

[0021] Furthermore, the pad is covered with a packaging adhesive layer.

[0022] A display screen comprises the lamp bead structure.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] By providing a thinning structure on the pad, the thinning structure can accommodate the flowing solder paste during soldering;

[0025] If the volume of solder paste during printing is too small, the solder paste will flow downward during printing or soldering, and will preferentially gather and fill in the thinned structure, thereby enhancing the bonding force between the chip and the pad.

[0026] If the volume of solder paste during printing is too large, the solder paste will flow into the thinning structure, increasing the overall solder absorption on the pad surface, thereby improving the chip tilt caused by the large volume of solder paste during printing.

[0027] At the same time, the present invention provides a transition slope at the edge of the thinning structure, making the connection between the thinning structure and the pad surface smoother, allowing the solder paste to be more evenly distributed on the pad during printing, thereby improving the soldering yield and the flowability of the solder paste, and reducing the graying and blackening of the pad surface when the solder paste volume is too small. Furthermore, the LED chip generates heat during operation, and the transition slope at the edge of the thinning structure helps dissipate the heat, thereby improving thermal management performance and extending the service life of the LED chip.

[0028] Other features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0030] Figure 2 This is an enlarged cross-sectional view of the structure of Example 1;

[0031] Figure 3 is a cross-sectional view of the overall structure of embodiment 1;

[0032] Figure 4 It is an enlarged cross-sectional view of the structure of the second embodiment.

[0033] The reference numerals in the figures are:

[0034] 1. Substrate; 2. Solder pad; 21. Thinning structure; 22. Transition slope; 3. Light-emitting chip; 4. Solder mask; 5. Solder paste; 6. Encapsulation adhesive layer. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal communication of two components or the interaction relationship between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0036] Example 1

[0037] A lamp bead structure, such as Figure 1 and Figure 2 As shown, including:

[0038] substrate1;

[0039] A pad 2 connected to the substrate 1 and having a thinning structure 21;

[0040] A solder resist 4 is provided on the surface of the pad 2;

[0041] Solder paste 5, the solder paste 5 is disposed on the surface of the solder pad 2, and the solder paste 5 is disposed in the thinning structure 21;

[0042] The light-emitting chip 3 is connected to the pad 2 via solder paste 5 .

[0043] The present application provides a thinning structure 21 on the main body of the pad 2 so that the thinning structure 21 can accommodate the flowing solder paste 5. Specifically, the thinning structure 21 is a depression. Optionally, the depression can be obtained through a thinning process.

[0044] When the solder paste 5 is printed, if the volume of the solder paste 5 is too small, the surface of the normal pad 2 will turn gray and black after reflow soldering, and there will be no solder paste 5 gathered at the bottom of the chip, resulting in basically no bonding force between the chip and the pad 2, and low product reliability; however, the present application provides a thinning structure 21 on the main body of the pad 2, so that the bottom surface of the thinning structure 21 is lower than the surface of the main body of the pad 2, so that the solder paste 5 flows downward during printing, and preferentially gathers and fills in the thinning structure 21, so as to enhance the bonding force between the chip and the pad 2.

[0045] When printing solder paste 5, if the volume of solder paste 5 is too large, the surface of the normal pad 2 will have a large curvature after reflow, tilting the top of the chip and affecting the consistency of the light-emitting angle. However, the present application provides a thinning structure 21 to accommodate the solder paste 5, increasing the overall solder capacity of the pad 2, thereby improving the chip tilt caused by the large volume of solder paste 5 during printing.

[0046] In this embodiment, the thickness of the pad 2 is 15 μm. Optionally, the height of the thinning structure 21 is 3 μm-7 μm. Preferably, the thickness of the thinning structure 21 is 5 μm. The present application sets the thickness of the thinning structure 21 to 5 μm to facilitate printing of a small volume of solder paste 5 and to facilitate accommodating an appropriate amount of solder paste 5 when printing a large volume of solder paste 5.

[0047] The substrate 1 is a resin substrate 1 , and preferably, the substrate 1 is a BT board.

[0048] The present application uses a non-metallic substrate 1 to prevent the solder paste 5 from flowing through the substrate 1, reduce defects that may occur during the use of the solder paste 5 due to the provision of a thinning structure 21, and avoid the solder paste 5 from drawing or sharpening, thereby improving the welding quality and reliability.

[0049] In this embodiment, the length of the thinning structure 21 is greater than the length of the light emitting chip 3 , and the width of the thinning structure 21 is greater than the width of the light emitting chip 3 .

[0050] In the present application, the length of the thinning structure 21 is greater than the length of the light-emitting chip 3 , and the width of the thinning structure 21 is greater than the width of the light-emitting chip 3 , so as to accommodate the light-emitting chip 3 and facilitate the light-emitting chip 3 to contact the pad 2 through the solder paste 5 .

[0051] like Figure 3 As shown, optionally, the pad 2 is further covered with an encapsulation layer 6, which covers the pad 2, solder paste 5 and the light-emitting chip 3 to achieve encapsulation. Specifically, the encapsulation layer 6 is formed by encapsulation glue, which is a prior art and will not be described in detail in this application.

[0052] In this embodiment, the pad 2 is a metal pad 2 , and the light-emitting chip 3 is a flip-chip LED chip.

[0053] A display screen comprises the lamp bead structure.

[0054] Example 2

[0055] like Figure 4 As shown, the difference between this embodiment and the first embodiment is that a transition slope 22 is provided on the edge of the thinning structure 21 .

[0056] The present application sets a transition slope 22 on the edge of the thinning structure 21, so that the connection between the thinning structure 21 and the surface of the pad 2 is smoother, so that the solder paste 5 is more evenly distributed on the pad 2 during printing, thereby improving the welding yield, improving the flow ability of the solder paste 5, and reducing the phenomenon of the pad 2 surface becoming gray and black when the volume of the solder paste 5 is small.

[0057] Furthermore, the LED chip generates heat during operation. Providing a transition slope 22 at the edge of the thinning structure 21 helps to dissipate the heat, thereby improving the thermal management performance and extending the service life of the LED chip.

[0058] The length of the transition slope 22 is 5 μm-10 μm.

[0059] The thinning structure 21 is an etched structure, which is formed by etching, specifically, by an etching method in a thinning process.

[0060] The present application forms the thinning structure 21 by using an etching process, which facilitates the generation of the transition slope 22 and helps to save manufacturing costs.

[0061] The lamp bead structure and display screen provided by the utility model have simple structure, convenient use and high reliability.

[0062] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A lamp bead structure, characterized in that: include: substrate; a soldering pad connected to the substrate, wherein a thinning structure is provided on the soldering pad; Solder paste, the solder paste being disposed on the surface of the solder pad and the solder paste being disposed in the thinning structure; A light-emitting chip is connected to the pad via solder paste, and the light-emitting chip is arranged on the thinned structure.

2. The lamp bead structure according to claim 1, characterized in that: The thinning structure is a depression, and the height of the thinning structure is 3 μm-7 μm.

3. The lamp bead structure according to claim 2, characterized in that: The edge of the thinning structure is provided with a transition slope.

4. The lamp bead structure according to claim 3, characterized in that: The length of the transition slope is 5 μm-10 μm.

5. The lamp bead structure according to claim 2, characterized in that: The thinning structure is an etched structure.

6. The lamp bead structure according to any one of claims 1 to 5, characterized in that: The length of the thinning structure is greater than the length of the light emitting chip, and the width of the thinning structure is greater than the width of the light emitting chip.

7. The lamp bead structure according to claim 6, characterized in that: Also included is a solder resist, which is arranged on the surface of the pad.

8. The lamp bead structure according to claim 6, characterized in that: The substrate is a resin substrate.

9. The lamp bead structure according to any one of claims 1-5, 7 or 8, characterized in that: The pad is covered with a packaging adhesive layer.

10. A display screen, characterized in that: The invention comprises the lamp bead structure according to any one of claims 1 to 9.

Images