CN212907789U

CN212907789U - Dam, mounting base and light emitting diode

Info

Publication number: CN212907789U
Application number: CN202022556554.3U
Authority: CN
Inventors: 王维昀; 王新强; 李永德; 王后锦; 康俊杰; 袁冶; 罗巍
Original assignee: Songshan Lake Materials Laboratory
Current assignee: Songshan Lake Materials Laboratory
Priority date: 2020-11-06
Filing date: 2020-11-06
Publication date: 2021-04-06
Anticipated expiration: 2030-11-06

Abstract

A dam, a mounting seat and a light-emitting diode belong to the field of light-emitting diodes. The box dam comprises a dam body and a metal layer. The dam body is provided with a dam hole limited by a dam wall, and the dam hole penetrates through the dam body in the thickness direction. The metal layer is arranged on the dam body and is constructed as a connecting structure of the surrounding dam and the lens. The dam body is provided with the metal layer, so that the metal layer and the lens can be connected in a reflow soldering and eutectic soldering mode to achieve high-air-tightness installation of the lens, and the service life of the light-emitting diode based on the metal layer is prolonged.

Description

Dam, mounting base and light emitting diode

Technical Field

The application relates to the field of light emitting diodes, in particular to a box dam, a mounting seat and a light emitting diode.

Background

An LED (Light Emitting Diode, abbreviated as LED) package device has a high requirement on air tightness, and thus has a high requirement on package quality. Generally, an organic material such as silicone gel or epoxy is used as a sealing material for an LED device. However, Ultraviolet LEDs, especially UV-C (Ultraviolet C, abbreviated as UV-C) Ultraviolet LEDs, can cause photodegradation of organic materials, aging and even cracking of the materials, resulting in reduced hermeticity.

SUMMERY OF THE UTILITY MODEL

In order to improve, even solve the poor problem of installation gas tightness of lens among the emitting diode, this application has proposed a box dam, mount pad, emitting diode.

The application is realized as follows:

in a first aspect, examples of the present application provide a dam for connecting a substrate and a lens in a light emitting diode.

The box dam comprises a dam body and a metal layer. The dam body is provided with a dam hole limited by a dam wall, and the dam hole penetrates through the dam body in the thickness direction. The dam body is made of inorganic non-metallic materials. The metal layer is arranged on the dam body and is constructed as a connecting structure of the surrounding dam and the lens.

The dam is provided with a metal layer so that the metal layer can be used as a component connected to the lens in the light emitting diode. Therefore, the dam and the lens can be connected in a firm and high-air-tightness mode through reflow soldering or eutectic soldering and the like, and the service life of the light-emitting diode is prolonged. Furthermore, the metal layer is also resistant to the photo-aging effects of ultraviolet light, which can be advantageously applied to light emitting diodes, in particular short wavelength ultraviolet light emitting diodes (UV-C LEDs). Moreover, the box dam is connected with the lens by the metal layer in a reflow soldering or eutectic soldering mode and the like, so that overlarge thermal expansion coefficient difference is avoided, and the falling risk is avoided.

According to some examples of the application, the box dam includes one or more of the following limitations:

a first definition: the cross section of the dam hole is square, round or rectangular;

the second definition: the metal layer is arranged on the partial upper surface or the whole upper surface of the dam body;

the third limitation is that: the metal layer is arranged on the partial upper surface of the dam body and is annularly arranged.

In a second aspect, the present examples provide a mount that includes a substrate, a dam. The substrate and the box dam are arranged in a laminated mode, and the box dam is connected with the substrate through the surface deviating from the metal layer in the thickness direction.

According to some examples of the present application, a substrate has a first contact layer;

the dam body of the box dam is provided with a second contact layer, and the second contact layer is positioned on the surface of the dam body deviating from the metal layer along the thickness direction;

the substrate is connected with the second contact layer of the box dam through the first contact layer, and the first contact layer and the second contact layer are made of metal materials respectively.

According to some examples of the application, the substrate and the dam are connected by plating or soldering or eutectic soldering.

Optionally, the support is made of metal.

According to some examples of the application, the substrate is provided with a heat sink at a surface facing away from the first contact layer, the first contact layer being electrically connected to the heat sink.

Optionally, the substrate has a through hole, a conductive material is disposed in the through hole, and the first contact layer is electrically connected to the heat sink through the conductive material.

According to some examples of the application, the surface of the substrate facing the box dam is provided with a die bonding area, the die bonding area is provided with a die bonding electrode, the surface of the substrate facing away from the box dam is provided with a back electrode, and the die bonding electrode is electrically connected with the back electrode.

Optionally, the die attach electrode is electrically connected to the back electrode through a via hole in the substrate, and the via electrode is disposed in the via hole.

In a third aspect, the present examples provide a light emitting diode comprising a light emitting chip, a mount, and a lens. The light-emitting chip is fixed on the substrate in the mounting seat; the lens is suspended to cover the box dam and is connected with the metal layer of the box dam.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a schematic structural view of an exemplary box dam of the present application;

FIG. 2 is a schematic structural view of a mount in an example of the present application;

FIG. 3 shows a schematic structural view of a dam in the mount of FIG. 2;

FIG. 4 shows a schematic view of the substrate in the mount of FIG. 2 from a first perspective;

FIG. 5 shows a schematic view of the substrate in the mount of FIG. 2 from a second perspective;

FIG. 6 shows a schematic view of the substrate in the mount of FIG. 2 from a third perspective;

FIG. 7 shows a cross-sectional structural view along B-B in the mount of FIG. 6;

FIG. 8 shows a cross-sectional structural view along C-C in the mount of FIG. 6;

FIG. 9 shows a cross-sectional structural view along D-D in the mount of FIG. 6.

Icon: 100-box dam; 101-dam wall; 1011-dam hole; 1012-upper surface; 102-a metal layer; 103-a second contact layer; 200-a mounting seat; 201-a substrate; 202-die bond electrode; 203-a first contact layer; 204-back electrode; 205-heat sink; 301-conducting electrodes; 302-conductive material.

Detailed Description

Embodiments of the present application will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present application and should not be construed as limiting the scope of the present application. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The UV-C ultraviolet LED can generate ultraviolet light with the wavelength of 200-280nm, so that the light emitted by the LED of the type has higher energy, thereby generating stronger thermal effect on each part in the LED. Thermal effects can cause thermal expansion of various components in the LED device, which can cause delamination or even detachment of various interconnect layers from each other when the coefficients of expansion of the various components are not matched.

In addition, when packaging each component to fabricate an LED device, organic materials such as silicone gel and epoxy are often used as sealing materials. These organic materials are easily degraded by UV-C UV rays, which can age and even crack, which can also cause the various interconnect layers to delaminate and even break away from each other.

When the above-mentioned delamination problem occurs, the sealing property of the LED device is also deteriorated, and thus the LED device is easily affected by oxygen, moisture, and the like in the environment, further deteriorating the performance and lifetime of the LED device.

Generally, an LED device mainly includes a substrate, a dam, a light emitting chip, and a lens.

Through the above analysis of the structure and the present situation of LED devices, especially UVC ultraviolet LED devices, the inventors found that there are mainly some problems as follows: the connection between the substrate and the box dam and between the box dam and the lens is made of organic materials, and the thermal expansion coefficients are not matched. The connection between the dam and the lens is not stable, and the problem that the sealing performance is easily reduced is particularly remarkable.

In view of the above, in the present application, the dam in the LED device is selected to be modified so as to be tightly and firmly connected to the lens, and accordingly, the air tightness is improved. Exemplary structures please refer to fig. 1-9.

It should be noted that although the LED device is described as an example in the present application, this does not mean that the solution of the present application can only be applied to the LED device. It may also be selected for use in fabricating other components for power semiconductor packaging, such as substrates.

In one example, a metal layer (e.g., a metal plating layer, or a solder metal layer) is disposed on the upper surface of the dam. The metal layer can be connected with the lens of the LED in a good airtight mode through solder paste reflow soldering, tin-gold eutectic soldering and the like.

Accordingly, the present application proposes a dam 100 which can connect a substrate 201 and a lens in a light emitting diode and can provide good connection airtightness, particularly airtightness of a connection between the dam and the lens.

Referring to fig. 1, the dam 100 includes a dam body and a metal layer 102.

Wherein the dam body has a dam wall 101. The dam wall 101 is substantially plate-like in configuration. A dam hole 1011 is provided at a substantially central portion of the dam wall 101, and the dam hole 1011 penetrates the dam wall 101 in the thickness direction. The dam hole 1011 may be formed by laser cutting on a ceramic substrate such as alumina used to form the dam.

The dam aperture 1011 formed in the dam wall 101 may be of any suitable shape. Shown in fig. 1 is a dam hole 1011 having a rectangular cross-sectional shape. In other examples, the shape may be circular, square, or polygonal, which is not specifically limited in this application. Typically the dam wall 101 has a greater thickness relative to the metal layer 102 in order to be able to accommodate the light emitting chips.

Generally, the dam 100 (mainly implemented as a dam body) may be made of a metal material (such as copper), which can protect the LED light emitting chip and facilitate the installation of the lens structure. However, considering that the dam 100 made of metal is prone to crack due to the difference between the thermal expansion coefficients of the dam 100 and the ceramic substrate 201 in the LED, the dam 100 may be made of non-metal materials, i.e., the dam wall 101 in the present example may be made of non-metal materials such as glass, ceramic, sapphire, etc. Illustratively, the ceramic comprises an alumina ceramic or an aluminum nitride ceramic. Wherein the aluminum nitride ceramic has a high thermal conductivity of 150-220W/m.K. Therefore, compared with the traditional alumina ceramic, the aluminum nitride ceramic with high thermal conductivity is more suitable for serving as a packaging substrate of a high-power LED, especially a high-power ultraviolet LED.

The metal layer 102 is disposed on the dam, such as the upper surface 1012 of the dam wall 101. Also, the metal layer 102 is configured as a connection structure of the dam 100 and the lens. Illustratively, the material from which the metal layer 102 is fabricated is bonded to the upper surface 1012 of the dam by a thin film process.

The metal layer 102 may be a partial region covering the upper surface 1012 of the dam wall 101 (as in the embodiment shown in fig. 1). Alternatively, in other examples, the metal layer 102 covers the entire area of the upper surface 1012 of the dam wall 101, or the metal layer 102 extends over the entire upper surface 1012 of the dam, i.e., in a direction perpendicular to the dam wall 101, and the projections of the dam 100 and the metal layer 102 coincide.

In order to ensure the air tightness between the dam 100 and the lens connection portion, a metal layer 102 is disposed at the contact portion between the dam and the lens connection portion. Thus, metal layer 102 may be configured as a ring structure, as shown in fig. 1.

The metal layer 102 may be a single metal material, or an alloy or mixture of multiple metals. Illustratively, the metal layer 102 contains one or a combination of Ti (titanium), Cu (copper), Ni (nickel), Pb (lead), Au (gold), Sn (tin), and Ag (silver). As for the combination manner, there may be a combination of two kinds, a combination of three kinds, a combination of four kinds, or the like. For example, the metal material contains both Ti and Cu, or Ni and Au; alternatively, the metal layer 102 contains Pb and Sn or Ag at the same time, or the like.

Based on the structure of the dam 100, the example proposes a lens mounting method for a light emitting diode, which includes covering a lens (or window sheet) on the metal layer 102 of the dam 100, and performing inorganic soldering by means of reflow soldering or eutectic soldering. The corresponding connecting part of the lens is also manufactured in advance by manufacturing a metal material for welding, and can be manufactured by a mode such as electroplating. The lens and the dam 100 may be overlapped and substantially aligned when they are soldered, and then self-alignment of the lens is achieved by surface tension when the solder is melted during soldering (e.g., reflow soldering).

When the light emitting diode is a UVC light emitting diode, quartz, sapphire and high borosilicate glass can be selected as the manufacturing materials of the lens because the transmittance of common glass to ultraviolet rays is low.

As an example of an application based on the structure of the dam 100, the present application also proposes a light emitting diode (not shown). The light emitting diode includes a light emitting chip, a mount 200, and a lens. The light emitting chip is fixed in the mounting base 200, and the lens is suspended to cover the mounting base 200. More specifically, the light emitting chip is fixed in the substrate 201 of the mount 200, and the lens is connected with the metal layer 102 of the dam 100 in the mount 200.

The material of the lens can be properly adjusted according to different light-emitting wavelengths of the light-emitting chips. Generally, the lens can be made of common glass, and when the transmittance of the lens to the light generated by the light emitting chip does not meet the requirement, the material for making the lens can be adjusted.

In particular, the mounting seat 200 is mainly composed of a substrate 201 and a box dam 100, as shown in fig. 2. The substrate 201 and the dam 100 together define a mounting space to accommodate the light emitting chip. Further, the substrate 201 and the dam 100 are stacked. Corresponding to the case where the dam 100 has the metal layer 102, the dam 100 is connected to the substrate 201 with the surface facing away from the metal layer 102 in the thickness direction.

The substrate 201 may be selected as a ceramic substrate 201, i.e. the substrate 201 is made of a ceramic material. Illustratively, the ceramic material may be an alumina ceramic or an aluminum nitride ceramic. As mentioned above, the dam wall 101 of the dam 100 may be made of glass, ceramic or sapphire, and the ceramic may be alumina ceramic or aluminum nitride ceramic. In other words, the body (i.e., the dam wall 101) of the dam 100 and the substrate 201 can be made of ceramic materials. It should be noted that, although ceramic materials may be selected for the dam wall 101 and the substrate 201, the material does not mean that the same material is used for both. The two may be the same ceramic material or different ceramic materials.

By manufacturing the dam and the substrate 201 from the same or different ceramic materials, respectively, the matching of the thermal expansion coefficients of the two can be improved. In addition, in order to improve the firmness of the connection between the substrate and the metal layer and improve the weldability of the substrate 201 and the metal layer, the first contact layer 203 is arranged on the substrate, the second contact layer 103 is arranged on the dam body of the box dam 100 correspondingly, and the second contact layer 103 is arranged on the surface of the dam body, which is far away from the metal layer 102 in the thickness direction. Thus, the dam body of the dam 100 has a double-sided attachment structure, i.e., the metal layer 102 and the second contact layer 103.

When the substrate 201 is combined with the dam 100, the first contact layer 203 and the second contact layer 103 are combined by means of, for example, electroplating, and as an option for adapting to an electroplating scheme, the first contact layer 203 and the second contact layer 103 are respectively made of metal materials (which may be the same metal material or different metal materials). Illustratively, the first contact layer 203 on the substrate 201 may be formed on the surface of the substrate 201 by Direct Copper Plating (DPC). Similarly, the second contact layer 103 can be formed on the lower surface of the dam body of the dam 100 by a direct copper plating process.

Thus, in manufacturing the LED device, the substrate 201 and the dam 100 may be brought close to and maintained at a selected interval by a jig or other fixing means, and then plated by connecting a plating apparatus so that the first contact layer 203 and the second contact layer 103 are simultaneously plated and integrated by growing a plating material (expressed as a plating layer). In other examples, the substrate 201 and the dam body of the dam 100 may be connected in other manners, such as welding the first contact layer 203 and the second contact layer 103.

In the case where the substrate 201 and the dam 100 are provided with the aforementioned contact layers, and in the case of connection by electroplating, in order to maintain thickness uniformity of a plating layer (not shown) or bonding firmness of the plating layer and the two contact layers, a support (not shown) may be provided between the substrate 201 and the dam 100 during the manufacturing process, and the dam body of the dam 100 and the substrate 201 may be spaced apart by the support to form a gap of a given interval. The support body can be selected from non-metallic materials. For example, the dam 100 and the substrate 201 are relatively pressed and held and fixed. Thereby, there is a support between the two, so that it can be ensured that the gap distance between the two is determined and constant, and the first contact layer 203 and the second contact layer 103 are located in the gap, thereby enabling the two contact layers to form a plating environment that remains stable (e.g., relatively static) for stable and consistent growth of the plating layer.

In addition, the substrate 201 of the mount 200 may also be provided with a heat sink 205, based on the need for plating power. In one example, the substrate 201 is provided with a heat sink 205 at a surface facing away from the first contact layer 203, see fig. 5. Accordingly, the heat sink 205 and the first contact layer 203 are respectively located on both side surfaces of the substrate 201 in the thickness direction, as shown in fig. 8. The surface in which the first contact layer 203 is disposed may generally be considered a front surface, while the surface in which the heat sink 205 is disposed may generally be considered a back surface. As an alternative example, the first contact layer 203 and the heat sink 205 may be fabricated by using a thin film process, an electroplating process, or the like.

For the implementation manner of electrically connecting the first contact layer 203 and the heat sink 205, optionally, the substrate 201 is provided with a through hole along the thickness direction, and the through hole is filled with the conductive material 302, so that the first contact layer 203 is electrically connected with the heat sink 205 through the conductive material 302, see fig. 6 and 7. In this manner, the electroplating apparatus may provide electrical power to the first contact layer 203 directly through the heat sink 205 during electroplating. The through-holes therein may be implemented in various suitable ways, such as laser rapid printing, for example. The size of the through hole may be arbitrary, and illustratively, the through hole is a cylindrical hole and has a diameter of 0.05 to 0.2 mm.

Based on the need of mounting the light emitting chip, the surface of the substrate 201 facing the dam 100 has a die bond region, and correspondingly, a die bond electrode 202 as shown in fig. 4 is disposed in the die bond region, while the surface of the substrate 201 facing away from the dam 100 has a back electrode 204. The die bond electrode 202 is electrically connected to the back electrode 204, and both can be fabricated by using a thin film process and an electroplating process. The fixed electrodes are electrically connected to the light emitting chips and are fixed on the substrate 201, and the back electrodes 204 are electrically connected to the positive and negative electrodes of the power supply for supplying power to the light emitting chips.

In the example, the die attach electrode 202 and the back electrode 204 are each configured as a planar plate-like structure, such as a stripe structure. And the electrical connection is realized by disposing the conductive electrode 301, please refer to fig. 6 and fig. 9 together. As an example of disposing the via electrode 301, in some examples, the substrate 201 has a via hole (e.g., a cylindrical through hole) in which the via electrode 301 is filled, and both ends of which are in electrical contact with the die attach electrode 202 and the back surface electrode 204, respectively. The via may be implemented by vertically fabricating a through channel on the substrate 201 through a laser rapid printing process. The vias may be configured in the same manner as the previously described through-holes for configuring the heat sink 205, e.g., all cylindrical holes. Accordingly, the diameter of the via may be, for example, 0.05 to 0.2 mm.

In summary, by implementing the scheme, at least some of the following advantages can be achieved.

(1) In the hot pressing process, the ceramic substrate of the aluminum nitride is attached and connected with the dam structure. In contrast, in the present embodiment, the substrate and the dam are bonded by using an electroplating process based on the embodiment of providing the first contact layer and the second contact layer. Therefore, the scheme belongs to a low-temperature process, and can avoid the heat damage of the original circuit metal of the ceramic substrate caused by high temperature, so that the reliability of the product is further improved. Because the process of filling joints (gaps exist before the substrate and the enclosing plate are combined) in an electroplating mode is adopted, the influence of high temperature on the product quality is effectively avoided, and the process is simplified, energy is saved, and the mass production is facilitated.

(2) Be different from the LED device that uses metal material's box dam, LED device adopts borosilicate glass, alumina ceramics or artifical sapphire preparation non-metal material's box dam in this application scheme. The expansion coefficient of the nonmetal material old dam is more matched with the expansion coefficient of the aluminum nitride ceramic substrate.

(3) Different from the metal box dam made of metal, the box dam made of non-metal materials adopted by the application is more matched with the expansion coefficient of the material of the lens or the window piece required to be used by UV-LED packaging.

(4) According to the technical scheme, the metal layer used for welding the box dam and the lens or the window sheet is arranged on the upper surface of the box dam. Therefore, high-strength and high-airtightness connection of the dam structure and the lens (and accordingly the connecting portion of the lens also has a metal material) or the window sheet can be achieved by reflow soldering, eutectic soldering, or the like.

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are clearly and completely described in the above with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it is to be noted that the terms "center", "upper", "lower", "inner", "outer", and the like refer to the orientation or positional relationship shown in the drawings, or the orientation or positional relationship which the product of the application is conventionally placed in use, which are merely for convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

In the description of the present application, it is further noted that, unless expressly stated or limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A dam for connecting a substrate and a lens in a light emitting diode, the dam comprising:

the dam body is made of inorganic nonmetal materials and is provided with a dam hole limited by a dam wall, and the dam hole penetrates through the dam body in the thickness direction;

and the metal layer is arranged on the dam body and is constructed as a connecting structure of the dam and the lens.

2. The box dam of claim 1, wherein the box dam comprises one or more of the following definitions:

3. A mount, comprising:

a substrate;

a box dam according to claim 1 or 2;

the substrate is laminated with the box dam, and the box dam is connected with the substrate with the surface that deviates from the metal layer along the thickness direction.

4. The mount of claim 3, wherein the substrate is made of a ceramic, and the ceramic comprises an alumina ceramic or an aluminum nitride ceramic.

5. The mount of claim 4, wherein the substrate has a first contact layer;

6. The mount of claim 5, wherein the base plate and the dam are connected by plating or brazing or eutectic welding.

7. The mount of claim 5, wherein the substrate is provided with a heat sink on a surface facing away from the first contact layer, the first contact layer being electrically connected to the heat sink;

8. The mounting seat according to claim 3, wherein a surface of the substrate facing the dam has a die bond region, the die bond region is provided with a die bond electrode, a surface of the substrate facing away from the dam has a back electrode, and the die bond electrode is electrically connected with the back electrode.

9. The mounting socket according to claim 8, wherein the die attach electrode is electrically connected to the back electrode through a via, the substrate has a via, and the via is disposed in the via.

10. A light emitting diode, comprising:

a light emitting chip;

the mount of any one of claims 3 to 9, the light emitting chip being secured to a substrate in the mount;

and the lens is covered on the box dam in a suspension manner, and is connected with the metal layer of the box dam.