Device substrate and light-emitting device
By reducing the diameter of the transition lines and optimizing the substrate design of the flip-chip structure, the problem of unreasonable pad and transition line dimensions was solved, improving the chip die bonding flatness and light emission effect, and promoting device miniaturization.
Patent Information
- Application Number
- CN202522142132.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-10
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2035-10-10
AI Technical Summary
In traditional LED light-emitting devices, the unreasonable size design of the pads and transition lines leads to inconsistent shapes of the melted solder paste, affecting the flatness of the die bonding and the light output effect, and is also detrimental to the miniaturization of the device.
By reducing the wire diameter of the transition lines, the area of solder paste spreading in the molten state is reduced, optimizing the solder joint condition, improving the chip die bonding flatness and adhesion, and adopting a flip-chip substrate design to reduce the ink coverage area and improve structural stability.
The solder joint condition was optimized, which improved the bonding force between the chip and the pad and the structural stability of the device, enhanced the light emission effect and adapted to the miniaturization trend.
Smart Images
Figure CN223540885U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of light-emitting device technology, and in particular to a device substrate and a light-emitting device. Background Technology
[0002] In the field of semiconductor device technology, for LED light-emitting devices with flip-chip structures, the size design of the transition lines between the pads on the BT substrate is a key factor affecting the shape of the solder joints. In traditional device structure designs, a certain amount of space is usually reserved as a buffer, meaning that the size of the pads and transition lines is designed to be larger than the actual requirements, and the line diameter of the transition lines is usually designed to be larger than the side length of the pads. The actual dimensions are not regular, which leads to uneven melting and spreading of the solder paste on the pads after reflow, resulting in poor solder joint condition, affecting the flatness of the chip after die bonding, directly affecting the light emission effect, and hindering the trend of device miniaturization. Utility Model Content
[0003] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a device substrate and a light-emitting device. By reducing the wire diameter of the transition line, the area of solder paste melting and spreading is reduced, the state of the formed solder joint is optimized, the flatness of the chip die bonding is improved, and the structural stability and light emission effect of the device are optimized.
[0004] This utility model provides a device substrate, which includes a substrate body and a front circuit is provided on the front side of the substrate body.
[0005] The front circuitry includes a plurality of front pads and metal lines, wherein the plurality of front pads are connected to the metal lines respectively.
[0006] A transition line is provided at the connection between the front pad and the corresponding metal line. The relationship between the side length a of the front pad and the wire diameter b of the transition line is: 0 < 2b < a.
[0007] Furthermore, the side length 'a' of the front pad is in the range of 80um ≤ a ≤ 100um.
[0008] Furthermore, the relationship between the connection width c of the transition line and the wire diameter b of the transition line is: 0 < b ≤ c.
[0009] Furthermore, the range of the wire diameter b1 on the upper surface of the transition line is: 25um≤b1≤50um.
[0010] Furthermore, the range of the wire diameter b2 on the lower surface of the transition line is: 25um≤b2≤50um.
[0011] Furthermore, a back circuit is provided on the back side of the substrate body, and the back circuit includes a plurality of back pads.
[0012] Furthermore, the side length e of the back pad is in the range of 30um≤e≤50um.
[0013] Furthermore, the substrate body is provided with a plurality of perforated rings, which penetrate the substrate body, and the front circuit is connected to the back circuit based on the corresponding perforated rings.
[0014] Furthermore, the front side of the substrate body is also provided with front ink, which covers the metal lines and the hole ring.
[0015] Furthermore, the front side of the substrate body is also provided with front ink, which covers the area on the front side of the substrate body other than the plurality of front pads and transition lines.
[0016] Furthermore, the thickness h1 of the front ink has a range of 6um ≤ h1 ≤ 16um.
[0017] Furthermore, the back side of the substrate body is also provided with back ink, which covers the area on the back side of the substrate body other than the plurality of back pads.
[0018] Furthermore, the thickness h2 of the back ink has a range of 10um ≤ h2 ≤ 20um.
[0019] Furthermore, identification ink is also provided on the back side of the substrate body.
[0020] This utility model also provides a light-emitting device, which includes a light-emitting chip and the aforementioned device substrate, wherein the light-emitting chip is soldered onto the substrate body of the device substrate.
[0021] This invention provides a device substrate and a light-emitting device. By reducing the diameter of the transition lines, the area of the solder paste spreading on the pads and transition lines when it is in a molten state during the reflow process is reduced. This makes the solder paste molten spreading structure more consistent, optimizes the state of the formed solder joints, improves the flatness of the chip on the solder paste molten spreading structure, and improves the bonding force and stability between the chip and the pads. This further optimizes the structural stability and light emission effect of the device. Attached Figure Description
[0022] Figure 1 This is a first front view of the device substrate structure in Embodiment 1 of this utility model;
[0023] Figure 2 yes Figure 1Enlarged schematic diagram at point m;
[0024] Figure 3 This is a schematic cross-sectional view of the transition line structure in Embodiment 1 of this utility model;
[0025] Figure 4 This is a first schematic diagram of the back side of the device substrate structure in Embodiment 1 of this utility model;
[0026] Figure 5 This is a second front view of the device substrate structure in Embodiment 1 of this utility model;
[0027] Figure 6 This is a schematic cross-sectional view of the device substrate structure in Embodiment 1 of this utility model;
[0028] Figure 7 This is a second schematic diagram of the back side of the device substrate structure in Embodiment 1 of this utility model;
[0029] Figure 8 This is a front view of the device substrate structure in Embodiment 2 of this utility model;
[0030] Figure 9 This is a schematic diagram of the light-emitting device structure in Embodiment 3 of this utility model. Detailed Implementation
[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.
[0032] In this invention, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of features, figures, steps, actions, components, portions or combinations thereof disclosed in this specification, and are not intended to exclude the possibility of the presence or addition of one or more other features, figures, steps, actions, components, portions or combinations thereof.
[0033] It should also be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.
[0034] Example 1
[0035] Embodiment 1 of this utility model provides a device substrate, which includes a substrate body and a front circuit is provided on the front side of the substrate body.
[0036] The front circuitry includes a plurality of front pads and metal lines, wherein the plurality of front pads are connected to the metal lines respectively.
[0037] A transition line is provided at the connection between the front pad and the corresponding metal line. The relationship between the side length a of the front pad and the wire diameter b of the transition line is: 0 < 2b < a.
[0038] In one optional implementation of this embodiment, such as Figure 1 As shown, Figure 1 The diagram shows a first front view of the device substrate structure in Embodiment 1 of the present invention. The device substrate includes a substrate body 1, and the front side of the substrate body 1 is provided with front lines.
[0039] Furthermore, the front circuitry includes six front pads 2 and metal lines 3, with the six front pads 2 correspondingly connected to the metal lines 3.
[0040] Specifically, the six front pads 2 are arranged in an array in the functional area in the center of the front side of the substrate body 1, and the metal lines 3 are distributed around the six front pads 2, that is, in the non-functional area on the periphery of the substrate body 1. The metal lines 3 are connected to the six front pads 2 respectively.
[0041] In one optional implementation of this embodiment, such as Figure 2 As shown, Figure 2 yes Figure 1 The enlarged schematic diagram at point m shows that a transition line 4 is provided at the connection between the front pad 2 and the metal line 3.
[0042] Specifically, the transition line 4 is disposed in the functional area in the center of the front side of the substrate body 1, and is used to connect the front pad 2 and the metal line 3.
[0043] Furthermore, the relationship between the side length a of the front pad 2 and the wire diameter b of the transition line 4 is: 0 < 2b < a.
[0044] Specifically, in traditional device structure design, a certain amount of space is usually reserved as a buffer. That is, the size of the pads and transition lines is designed to be larger than the actual requirements, and the diameter of the transition lines is usually designed to be larger than the side length of the pads (i.e., b > a in this embodiment). The actual size is not regular, which leads to the solder paste on the pads spreading out in an uneven shape after reflow, resulting in poor solder joint condition, affecting the flatness of the chip after die bonding, directly affecting the light emission effect, and hindering the trend of device miniaturization. Therefore, in this embodiment, the relationship between the side length a of the front pad and the diameter b of the transition line is designed as: 0 < 2b < a. By reducing the diameter of the transition line, the area of the solder paste spreading on the pads and transition lines when it is in a molten state during the reflow process is reduced, making the solder paste spreading structure more consistent, optimizing the state of the formed solder joints, improving the flatness of the chip on the solder paste spreading structure, improving the bonding force and stability between the chip and the pads, and further optimizing the structural stability and light emission effect of the device.
[0045] In an optional implementation of this embodiment, the side length a of the front pad 2 is in the range of 80um≤a≤100um.
[0046] Specifically, the side length 'a' of the front pad 2 can be one of 80um, 85um, 90um, 95um, or 100um, determined according to actual design requirements. In this embodiment, 90um is preferred.
[0047] It should be noted that, in this embodiment, the front pad 2 is a square pad.
[0048] In an optional implementation of this embodiment, the relationship between the connection width c of the transition line 4 and the wire diameter b of the transition line 4 is: 0 < b ≤ c.
[0049] Specifically, the connection width c of the transition line is designed to be greater than or equal to its wire diameter b. This is because when the solder paste melts and spreads, it will preferentially extend along the direction of the connection width c of the transition line. Therefore, the connection width c of the transition line must be designed to be greater than or equal to its wire diameter b to avoid overflow of the transition line when the solder paste melts and spreads.
[0050] In one optional implementation of this embodiment, such as Figure 3 As shown, Figure 3 A cross-sectional schematic diagram of the transition line structure in Embodiment 1 of this utility model is shown. The transition line 4 includes an upper surface 41 and a lower surface 42.
[0051] Furthermore, the range of the wire diameter b1 of the upper surface 41 of the transition line 4 is: 25um≤b1≤50um;
[0052] The range of the wire diameter b2 of the lower surface 42 of the transition line 4 is: 25um≤b2≤50um.
[0053] Specifically, the wire diameter b1 of the upper surface 41 of the transition line 4 can be one of 25um, 30um, 35um, 40um, 45um, and 50um, preferably 40um. The wire diameter b2 of the lower surface 42 of the transition line 4 can be one of 25um, 30um, 35um, 40um, 45um, and 50um, preferably 40um, and is determined according to actual design requirements.
[0054] Furthermore, the wire diameters of the upper surface 41 (b1) and lower surface 42 (b2) of the transition line 4 are not limited here. When the wire diameter of the upper surface 41 (b1) is greater than that of the lower surface 42 (b2), the state and shape of the solder joints formed by the solder paste melting and spreading structure are better controlled, the flatness is better, and the spreading is easier to control. However, considering the bonding force between the solder paste melting and spreading structure and the substrate body 1, it is also possible to design the wire diameter of the lower surface 42 (b2) to be greater than that of the upper surface 41 (b1). In this way, the bonding area between the solder paste melting and spreading structure and the substrate body 1 is larger, and the reliability is better. In this embodiment, priority is given to optimizing the state of the solder joints formed by the solder paste melting and spreading structure, and improving the flatness of the die bonding of the chip on the solder paste melting and spreading structure. Therefore, the scheme of the line diameter b1 of the upper surface 41 being larger than the line diameter b2 of the lower surface 42 is adopted. Here, the values of the line diameter b1 of the upper surface 41 and the line diameter b2 of the lower surface 42 of the transition line 4 and the size relationship between them can be determined according to the actual design requirements.
[0055] This section considers the performance of solder paste melting and spreading during the actual reflow process to further determine the wire diameter of the transition lines and optimize the consistency of the device structure.
[0056] In one optional implementation of this embodiment, such as Figure 4 As shown, Figure 4 The diagram shows a first schematic diagram of the back side of the device substrate structure in Embodiment 1 of this utility model. The back side of the substrate body 1 is provided with back circuitry, which includes four back pads 5.
[0057] Specifically, the four back pads 5 are connected to the metal lines 3, and the six front pads 2 are connected accordingly.
[0058] In an optional implementation of this embodiment, the side length e of the back pad 5 is in the range of 30um≤e≤50um.
[0059] Specifically, the side length e of the back pad 5 can be one of 30um, 35um, 40um, 45um, or 50um, depending on the actual design requirements.
[0060] In an optional implementation of this embodiment, the back pad 5 is a rectangular pad with a side length e including length e (e1) and width e (e2), and the length e (e1) and width e (e2) can take different values.
[0061] In an optional implementation of this embodiment, the substrate body 1 is further provided with four hole rings 6, which penetrate the substrate body 1, and the front circuit is connected to the back circuit based on the corresponding hole rings 6.
[0062] Specifically, the four hole rings 6 are respectively disposed at the four corners of the substrate body 1 and penetrate the substrate body 1. The front pads 2 and metal lines 3 in the front circuit are connected to the back pads 5 in the back circuit based on the corresponding hole rings 6, so as to realize the electrical connection of the device.
[0063] In an optional implementation of this embodiment, the front side of the substrate body 1 is further provided with front ink 7, which covers the metal line 3 and the hole ring 6.
[0064] Specifically, such as Figure 5 As shown, Figure 5 This shows a second schematic diagram of the front side of the device substrate structure in Embodiment 1 of this utility model. Figure 5 Compared to Figure 1 A marking has been added to the front ink. In this embodiment, the front ink 7 covers the metal line 3 and the via ring 6, but does not cover the front pad 2 and the transition line 4. Figure 5 The area filled by the intersecting lines is the area covered by the front ink 7.
[0065] This study considers LED light-emitting devices with a flip-chip structure. The BT substrate typically has ink applied to cover non-functional areas of the substrate to block reflected light from the chip illuminating the pads and transition lines in the functional areas, preventing interference with the overall display contrast. When the pads and transition lines are large, the ink can easily become over-covered, resulting in monotonous optical properties on the substrate surface and affecting light emission. Furthermore, the difference in thermal expansion coefficients between the ink and the BT substrate can cause substrate deformation, affecting the device's soldering accuracy and reliability. Therefore, in this embodiment, the ink on the front side of the device substrate is only applied to the metal lines and via rings, without covering other areas on the front side. This minimizes the ink coverage area, improving the substrate's appearance contrast while reducing the thermal expansion force between the ink and the substrate, thus reducing the risk of substrate deformation due to thermal expansion and improving the stability of the device structure.
[0066] Furthermore, since the BT substrate itself is darker than the front ink, in this embodiment, by reducing the coverage area of the front ink, the exposed area of the front of the BT substrate itself is increased, effectively improving the appearance blackness of the product.
[0067] In an optional implementation of this embodiment, the thickness h1 of the front ink 7 is in the range of 6um ≤ h1 ≤ 16um.
[0068] Specifically, the thickness h1 of the front ink 7 can be one of 6um, 8um, 10um, 12um, 14um, or 16um, depending on the actual design requirements.
[0069] Furthermore, such as Figure 6 As shown, Figure 6 This diagram shows a cross-sectional view of the device substrate structure in Embodiment 1 of the present invention. The thickness h1 of the ink 7 on the front side is as shown. Figure 6 As shown.
[0070] In one optional implementation of this embodiment, such as Figure 7 As shown, Figure 7 This shows a second schematic diagram of the back side of the device substrate structure in Embodiment 1 of this utility model. Figure 7 Compared to Figure 4 The back ink markings have been added, and the back side of the substrate body 1 is also provided with back ink 8, which covers the area on the back side of the substrate body 1 other than the plurality of back pads 5. Figure 7 The area filled by the intersecting lines is the area filled by the ink 8 on the back side.
[0071] In one optional implementation of this embodiment, such as Figure 6As shown, the thickness h2 of the back ink has a range of 10um ≤ h2 ≤ 20um.
[0072] Specifically, the thickness h2 of the back ink 8 can be one of 10um, 12um, 14um, 16um, 18um, or 20um, depending on the actual design requirements.
[0073] In an optional implementation of this embodiment, the back side of the substrate body 1 is further provided with identification ink 81.
[0074] In summary, Embodiment 1 of this utility model provides a device substrate that reduces the diameter of the transition lines, thereby reducing the area of the solder paste spreading on the pads and transition lines when it is in a molten state during the reflow process. This makes the solder paste molten spreading structure more consistent, optimizes the state of the formed solder joints, improves the flatness of the chip on the solder paste molten spreading structure, and enhances the bonding force and stability between the chip and the pads. This further optimizes the structural stability and light emission effect of the device.
[0075] Example 2
[0076] Embodiment 2 of this utility model provides a device substrate, such as Figure 8 As shown, Figure 8 This diagram shows a front view of the device substrate structure in Embodiment 2 of the present invention. The device substrate structure in Embodiment 2 is basically the same as that in Embodiment 1, except that:
[0077] In this second embodiment, the positions of the metal lines 3 and the hole rings 6 on the substrate body 1 of the device substrate are slightly changed;
[0078] In this second embodiment, the coverage area of the front ink 7 on the substrate body 1 of the device substrate is different. In this first embodiment, the front ink 7 only covers the metal lines 3 and the hole ring 6, and does not cover the front pads 2 and the transition lines 4. However, in this second embodiment, the front ink 7 covers the metal lines 3 and the hole ring 6, and also covers the area on the front of the substrate body 1 other than the front pads 2 and the transition lines 4, that is, part of the front area of the substrate body 1, so that the entire front ink 7 forms a near-circular closed area.
[0079] Furthermore, in this embodiment, the process of covering the front ink 7 with ink to form the front ink 7 is less difficult than in Embodiment 1, and it is more compatible with the relatively compact structure in this embodiment.
[0080] In summary, Embodiment 2 of this utility model provides a device substrate that reduces the diameter of the transition lines, thereby reducing the area of the solder paste spreading on the pads and transition lines when it is in a molten state during the reflow process. This makes the solder paste molten spreading structure more consistent, optimizes the state of the formed solder joints, improves the flatness of the chip on the solder paste molten spreading structure, and improves the bonding force and stability between the chip and the pads. This further optimizes the structural stability and light emission effect of the device.
[0081] Example 3
[0082] This utility model provides a light-emitting device in embodiment three. The light-emitting device includes a light-emitting chip and a device substrate as described in embodiment one or embodiment two. The light-emitting chip is soldered onto the substrate body of the device substrate.
[0083] In one optional implementation of this embodiment, such as Figure 9 As shown, Figure 9 A schematic diagram of the light-emitting device structure in Embodiment 3 of this utility model is shown. The light-emitting device includes a light-emitting chip 9 and a device substrate as in Embodiment 1. There are three light-emitting chips 9, which are soldered onto the front pads of the substrate body 1 of the device substrate.
[0084] In summary, Embodiment 3 of this utility model provides a light-emitting device, including the device substrate of Embodiment 1 or Embodiment 2. By reducing the wire diameter of the transition line, the area spread on the pads and transition line when the solder paste is in a molten state during the reflow process is reduced, making the solder paste molten spreading structure more consistent, optimizing the state of the formed solder joints, improving the flatness of the chip on the solder paste molten spreading structure, improving the bonding force and stability between the chip and the pads, and further optimizing the structural stability and light emission effect of the device.
[0085] The above provides a detailed description of a device substrate and a light-emitting device provided by the embodiments of this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.
Claims
1. A device substrate, characterized in that, The device substrate includes a substrate body, and the front side of the substrate body is provided with front circuitry. The front circuitry includes a plurality of front pads and metal lines, wherein the plurality of front pads are connected to the metal lines respectively. A transition line is provided at the connection between the front pad and the corresponding metal line. The relationship between the side length a of the front pad and the wire diameter b of the transition line is: 0 < 2b < a.
2. The device substrate as described in claim 1, characterized in that, The side length 'a' of the front pad is in the range of 80um ≤ a ≤ 100um.
3. The device substrate as described in claim 1, characterized in that, The relationship between the connection width c of the transition line and the wire diameter b of the transition line is: 0 < b ≤ c.
4. The device substrate as described in claim 1, characterized in that, The range of the wire diameter b1 on the upper surface of the transition line is: 25um≤b1≤50um.
5. The device substrate as described in claim 1, characterized in that, The range of the wire diameter b2 on the lower surface of the transition line is: 25um≤b2≤50um.
6. The device substrate as described in claim 1, characterized in that, The back side of the substrate body is provided with back circuitry, which includes a plurality of back pads.
7. The device substrate as described in claim 6, characterized in that, The side length e of the back pad is in the range of 30um≤e≤50um.
8. The device substrate as described in claim 6, characterized in that, The substrate body is also provided with a plurality of perforated rings, which penetrate the substrate body, and the front circuit is connected to the back circuit based on the corresponding perforated rings.
9. The device substrate as described in claim 8, characterized in that, The front side of the substrate body is also provided with front ink, which covers the metal lines and the hole ring.
10. The device substrate as described in claim 8, characterized in that, The front side of the substrate body is also provided with front ink, which covers the area on the front side of the substrate body except for the plurality of front pads and transition lines.
11. The device substrate as described in any one of claims 9-10, characterized in that, The thickness h1 of the front ink has a range of 6um ≤ h1 ≤ 16um.
12. The device substrate as described in claim 6, characterized in that, The back side of the substrate body is also provided with back ink, which covers the area on the back side of the substrate body other than the plurality of back pads.
13. The device substrate as described in claim 12, characterized in that, The thickness h2 of the back ink is in the range of 10um≤h2≤20um.
14. The device substrate as claimed in claim 1, characterized in that, The back side of the substrate body is also provided with identification ink.
15. A light-emitting device, characterized in that, The light-emitting device includes a light-emitting chip and a device substrate as described in any one of claims 1-14, wherein the light-emitting chip is soldered onto the substrate body of the device substrate.