LIGHT-EMITTING DIODE DEVICE AND METHOD FOR MANUFACTURING THE SAME

A light-emitting diode (LED) device includes a substrate, an LED chip, a light-transmissive element, and a bonding layer. The substrate has a first surface and a second surface opposite to the first surface in a thickness direction. The first surface has a functional region. The LED chip is disposed on the functional region of the first surface of the substrate. The light-transmissive element is disposed on the first surface of the substrate, and covers the LED chip. The bonding layer connects the substrate with the light-transmissive element, and is disposed on the substrate outside the functional region. The LED device has a surrounding surface. Cross sections of the surrounding surface in the thickness direction are straight lines that extend in the thickness direction.

FIELD

The disclosure relates to a semiconductor device, and more particularly to a light-emitting diode (LED) device and a method for manufacturing the same.

BACKGROUND

Light-emitting diode (LED) chips are rapidly developing because of their excellent performance. In particular, ultraviolet LEDs (e.g., a deep ultraviolet LED) have attracted much attention and became a hot research topic for having significant application values, especially in the field of sterilization.

With an increasing demand for the deep ultraviolet LEDs, a structure of a deep ultraviolet LED becomes more diverse. Currently, a packaging process for manufacturing the deep ultraviolet LED is performed by connecting a quartz glass to a substrate through a binder. However, such packaging process has many problems. For example, since the substrate and the quartz glass are made of different materials, the binder may not effectively bind the quartz glass to the substrate, resulting in poor airtightness of the deep ultraviolet LED. In addition, when binding the quartz glass to the substrate, an amount of the binder being used may not be accurately controlled. If the amount of the binder is too small, the binder may not be able to fully fill a gap between the substrate and the quartz glass, which may adversely affect the airtightness of the deep ultraviolet LED. If the amount of the binder being used is too much, an excess of the binder may overflow to a functional region of the deep ultraviolet LED, which may adversely affect a luminous efficiency thereof. Because the quartz glass is relatively hard and brittle, the quartz glass may be easily broken during the manufacturing of the deep ultraviolet LED, thereby reducing the airtightness and reliability of the deep ultraviolet LED.

Therefore, there is a need to improve the airtightness, luminous efficiency, and reliability of the deep ultraviolet LED.

SUMMARY

Therefore, an object of the disclosure is to provide a light-emitting diode (LED) device that can alleviate at least one of the drawbacks of the prior art.

According to a first aspect of the disclosure, an LED device includes a substrate, an LED chip, a light-transmissive element, and a bonding layer.

The substrate has a first surface and a second surface opposite to the first surface in a thickness direction. The first surface has a functional region. The LED chip is disposed on the functional region of the first surface of the substrate. The light-transmissive element is disposed on the first surface of the substrate, and covers the LED chip. The bonding layer connects the substrate with the light-transmissive element, and is disposed on the substrate outside the functional region. The LED device has a surrounding surface. Cross sections of the surrounding surface in the thickness direction are straight lines that extend in the thickness direction.

According to a second aspect of the disclosure, a method for manufacturing a light-emitting diode (LED) device includes the steps of:a) providing a wafer that has a first surface and a second surface opposite to the first surface, the first surface having a plurality of functional regions, the functional regions being separated from one another by dicing regions;b) providing a plurality of LED chips on the functional regions of the wafer, respectively;c) connecting a light-transmissive unit to the wafer through a plurality of first bonding layers so as to obtain a lighting workpiece, the first bonding layers being disposed on the wafer and being respectively located outside the functional regions, the light-transmissive unit covering the LED chips; andd) dicing the lighting workpiece along the dicing regions of the wafer, so as to form a plurality of LED devices.

DETAILED DESCRIPTION

Referring toFIG.1, a first embodiment of a light-emitting diode (LED) device100A according to the present disclosure includes a substrate101, a first metal layer1011a, a second metal layer1012a, an LED chip103, a light-transmissive element102, a bonding layer105, and a plurality of electrode pads1013.

The substrate101may be a ceramic substrate, a printed circuit board, or other suitable substrates. In this embodiment, the substrate101is a flat ceramic substrate. The substrate101has a first surface and a second surface opposite to the first surface in a thickness direction (O) (indicated by an arrow shown inFIG.1). The first surface of the substrate101has a functional region1011and a non-functional region1012that is located outside the functional region1011. The electrode pads1013are disposed on the second surface of the substrate101and are connected to the functional region1011. The functional region1011serves as a die bonding region on which the LED chip103is disposed. For example, the LED chip103may be connected to the functional region1011through gold wires or may be directly soldered to the functional region1011. In certain embodiments, the first metal layer1011ais formed on the functional region1011of the first surface of the substrate101. The first metal layer1011ahas positive and negative electrode regions that are connected to an electrode structure of the LED chip103, and the electrode pads1013are electrically connected to the positive and negative electrode regions of the first metal layer1011a, respectively.

There is no particular limitation on the LED chip103. For example, the LED chip103may be an ultraviolet LED chip or a deep ultraviolet LED chip that has an emission wavelength smaller than 400 nm, such as ranging from 220 nm to 385 m. In this embodiment, the LED chip103is the ultraviolet LED chip that has an emission wavelength ranging from 220 nm to 385 nm. The LED chip103may have a thickness ranging from 200 µm to 750 µm, such as from 250 µm to 500 µm or 450 µm. It is noted that the LED chip103may include a supporting substrate (not shown) and a semiconductor stack (not shown) formed on a surface of the supporting substrate. The semiconductor stack may include a first semiconductor layer, an active layer, and a second semiconductor layer that are sequentially formed on the surface of the supporting substrate. The electrode structure of the LED chip103may be connected to a respective one of the first and second semiconductor layers. The electrode structure of the LED chip103is connected to the functional region1011of the substrate101using methods such as soldering, eutectic bonding, or the like, so that the LED chip103may be fixed onto the substrate101.

The supporting substrate of the LED chip103may be a sapphire substrate, and the first semiconductor layer of the semiconductor stack may be an N-type aluminum gallium nitride (AlGaN) layer. The LED chip103may further include an aluminum nitride (AIN) buffer layer and an AIN/AIGaN superlattice layer that are disposed between the first semiconductor layer (e.g., the N-type AlGaN layer) and the supporting substrate (e.g., the sapphire substrate), thereby reducing lattice mismatch between the first semiconductor layer and the supporting substrate. The active layer may be an AlGaN multi-quantum well layer, and is disposed on a side of the first semiconductor layer that is distal from the supporting substrate. The second semiconductor layer of the semiconductor stack may be a P-type AlGaN layer, and is disposed on a side of the active layer that is distal from the supporting substrate.

The light-transmissive element102includes a mounting base1021and a light-transmissive region1022. The light-transmissive element102is connected to the substrate101through the bonding layer105that is disposed on the substrate101outside the functional region1011(i.e., disposed on the non-functional region1012).

In this embodiment, the light-transmissive element102is made of quartz glass and has a lens structure. The light-transmissive region1022is a convex lens, and the mounting base1021is connected to and surrounds the light-transmissive region1022. The mounting base1021is connected to the non-functional region1012, and the light-transmissive region1022is located above the LED chip103. In this embodiment, the LED device100A may further include a cavity104defined by the mounting base1021, the light-transmissive region1022, and the substrate101. The LED chip103is located in the cavity104. The cavity104may have a depth ranging from 100 µm to 900 µm in the thickness direction (O). It is noted that the LED device100A may further include a filler (not shown) in the cavity104, such as a reflective layer and/or an encapsulant that may contain a phosphor powder. In order to enhance the luminous efficiency of the LED device100A, a central line of the LED chip103overlaps a central line of the light-transmissive region1022(e.g., a convex lens) that passes through a geometry center of the light-transmissive region1022. Each of the central lines of the LED chip103and the light-transmissive region1022extends in the thickness direction (O).

In this embodiment, the light-transmissive region1022of the light-transmissive element102is a hemispherical convex lens. The geometry center of the light-transmissive region1022may be located at a position between a top surface103′ of the LED chip103and a bottom surface 102a of the light-transmissive region1022. The light-transmissive region1022(i.e., the hemispherical convex lens) may have a spherical diameter ranging from 2.00 mm to 3.50 mm, such as 3.20 mm. The light-transmissive element102may have a height in the thickness direction (O) that ranges from 1.50 mm to 2.30 mm, such as 2.10 mm. As shown inFIG.2, by having the light-transmissive element102, the LED device100A may have a light exiting angle of approximately 60°. The light exiting angle of the LED device100A may be adjusted depending on the filler in the cavity104between the mounting base1021and the light-transmissive region1022. For example, when the LED device100A includes no filler in the cavity104(i.e., only air or nitrogen is present in the cavity104), the light exiting angle of the LED device100A may range from 55° to 80°. For another example, when the LED device100A includes the filler in the cavity104(e.g., an inorganic gel or other reflective materials), the light exiting angle of the LED device100A may range from 80° to 120°.

Referring toFIG.1, the second metal layer1012ais formed on the non-functional region1012of the substrate101, and is formed as a metal strip that surrounds and is spaced apart from the functional region1011. The first metal layer1011aand the second metal layer1012amay be made of the same or different metallic materials. When the first metal layer1011aand the second metal layer1012aare made of the same metallic material, the first metal layer1011aand the second metal layer1012amay be formed simultaneously. Each of the first metal layer1011aand the second metal layer1012amay have a thickness in the thickness direction (O) that ranges from 30 µm to 100 µm, such as 50 µm.

As shown inFIG.1, the bonding layer105includes a first bonding layer1051. The first bonding layer1051includes a first portion1051athat is disposed on the second metal layer1012a, and a second portion1051bthat is disposed on at least a part of the substrate101outside the second metal layer1012a. It is noted that the second portion1051bmay be disposed on the substrate101at an outer side of the second metal layer1012aaway from the cavity104, and may fill a space between the mounting base1021and the substrate101.

The second metal layer1012aincreases a distance between a bottom surface of the mounting base1021and the first surface of the substrate101when the light-transmissive element102is connected to the substrate101through the first bonding layer1051, and accordingly, a distance between the bottom surface 102a of the light-transmissive region1022and the top surface103′ of the LED chip103, thereby preventing the LED chip103from being in move o with and damaged by the light-transmissive element102. In addition, the distance between the bottom surface 102a of the light-transmissive region1022and the top surface103′ of the LED chip103may be adjusted by adjusting the thickness of the second metal layer1012a. Such distance may be smaller than 100 µm, such as greater than 10 µm, so that the luminous efficiency of the LED chip103may be maintained under a premise that the LED chip103is not in contact with and damaged by the light-transmissive element102.

There is no particular limitation on the material for forming the second metal layer1012aas long as the second metal layer1012acan be used to increase the distance between the bottom surface of the mounting base1021and the first surface of the substrate101, and does not affect the photoelectric performance of the LED chip103. The second metal layer1012amay be made of, for example, but not limited to, a metal or an insulating material (e.g., silicon oxide or aluminum oxide that is formed by deposition).

In the thickness direction (O) of the LED device100A, the first bonding layer1051may have a thickness ranging from 35 µm to 150 µm. The first portion1051aof the first bonding layer1051may have a thickness ranging from 35 µm to 50 µm, and the second portion1051bof the first bonding layer1051may have a thickness ranging from 50 µm to 150 µm.

The first bonding layer1051may be made of one of silica gel, white glue, and fluorine resin, which may have one or more properties, such as better adhesion, a certain flowability, or a certain reflective function for reflecting light emitted from the LED chip103, thereby being able to increase the service life of the LED device100A while improving the airtightness thereof.

In practice, a material of the light-transmissive element102may depend on the light exiting angle of the LED device100A. In this embodiment, the light-transmissive element102is a lens made of quartz glass. In other embodiments, the light-transmissive element102may be a lens made of a plastic material.

As shown inFIG.1, in this embodiment, the substrate101has a sidewall that is aligned with a sidewall of the light-transmissive element102in the thickness direction (O), which is conducive for the LED device100A to be placed in a better location in a vibrator bowl feeder, and further enhancing a packaging yield of the LED device100A. By virtue of the first portion1051aof the first bonding layer1051uniformly and fully filling a space between the second metal layer1012aand the light-transmissive element102, there is no bubble or gap present therebetween, which is conducive for significantly enhancing the airtightness of the LED device100A. In addition, the second portion1051bof the first bonding layer1051that is formed on the part of the substrate101at the outer side of the second metal layer1012amay further prevent water vapor from entering an interior of the LED device100A. In particular, when the second portion1051bof the first bonding layer1051fills a space between the substrate101and the light-transmissive element102, the airtightness of the LED device100A can be further enhanced.

Referring toFIG.3, this disclosure also provides a method for manufacturing the first embodiment of the LED device100A according to the present disclosure, which includes the following consecutive steps S101to S104.FIGS.4to14illustrate intermediate stages of the method for manufacturing the first embodiment of the LED device100A.

In step S101, a wafer101′ is provided. The wafer101′ has a first surface (corresponding to the first surface of the substrate101) and a second surface (corresponding to the second surface of the substrate101) opposite to the first surface. The first surface of the wafer101′ has a plurality of the functional regions1011and a plurality of dicing regions1018. The functional regions1011are separated from one another by the dicing regions1018.

As shown inFIGS.4and5, the first surface of the wafer101′ further includes a plurality of the non-functional regions1012that are located in the dicing regions1018, and the electrode pads1013(not shown) are disposed on the second surface of the wafer101′ and are connected to the functional regions1011, respectively.

In certain embodiments, in this step, a plurality of the first metal layers1011aand a plurality of the second metal layers1012aare formed on the first surface of the wafer101′. A top surface of each of the first metal layers1011aand the second metal layers1012ais located at a level higher than that of the first surface of the wafer101′. The first metal layers1011aare formed on the functional regions1011, respectively, and the second metal layers1012aare formed as metal strips on the non-functional regions1012, respectively. Each of the second metal layers1012asurrounds and is spaced apart from a corresponding one of the functional regions1011. Two adjacent ones of the second metal layers1012adefine a trench106that is located in a respective one of the dicing regions1018.

In step S102, a plurality of the LED chips103are provided. The LED chips103are disposed on the functional regions1011of the first surface of the wafer101′, respectively, and are also disposed on the first metal layers1011a, respectively.

In certain embodiments, the LED chips103may be disposed on the wafer101′ in various ways. For example, as shown inFIG.6, each of the LED chips103and the wafer101′ has a square shape, and sides of each of the LED chips103are aligned with sides of the wafer101′, respectively. For another example, as shown inFIG.7, each of the LED chips103and the wafer101′ has a square shape, and each of the LED chips103is disposed on the wafer101′ in such a manner that four corners of each of the LED chips103point toward the four sides of the wafer101′, respectively. In certain embodiments, when the LED chip103has a relatively large size, the LED chip103may be disposed on the wafer101′ in a manner shown inFIG.7, which is capable of increasing space utilization of the wafer101′. In practice, the way that the LED chips103are disposed on the wafer101′ may be adjusted depending on the sizes of the LED chips103and the wafer101′. In certain embodiments, a zener diode 103a may be disposed on the wafer101′ (seeFIGS.6and7).

In step S103, as shown inFIGS.8to13, a light-transmissive unit1020is connected to the wafer101′ through a plurality of the first bonding layers1051, and covers the LED chips103, so as to obtain a lighting workpiece. The first bonding layers1051are disposed on the wafer101′, and are respectively located outside the functional regions1011(i.e., the dicing regions1018).

As shown inFIG.8, a binder material105′ fills the trenches106(seeFIG.4). In certain embodiments, the binder material105′ that fills the trenches106may have a height that measures from the first surface of the wafer101′ and that is greater than that of each of the first metal layers1011aon the functional regions1011and the second metal layers1012aon the non-functional regions1012. In certain embodiments, the height of the binder material105′ may be greater than that of each of the first metal layers1011aand the second metal layers1012ameasured from the first surface of the wafer101′ by a difference ranging from 50 µm to 200 µm. The binder material105′ may be made of one of silica gel, white glue, and fluorine resin. In this embodiment, the light-transmissive unit1020is made of quartz glass and covers the wafer101′. In addition, the light-transmissive unit1020includes a plurality of the light-transmissive elements102, each of which has a lens structure shown inFIG.1.

As shown inFIG.9, the structure shown inFIG.8is fixedly placed in an accommodating space (not shown) of a first fixture1015. The first fixture1015includes a first positioning element1016on a top portion of a sidewall of the first fixture1015. In this embodiment, the first positioning element1016is a positioning spring, and the first fixture1015has at least two of the first positioning elements1016. The number of the first positioning element1016may vary depending on actual requirements. It is noted that there is no particular limitation on the first positioning element1016as long as it can perform its intended function.

As shown inFIG.10, the light-transmissive unit1020is placed in an accommodating space (not shown) of a second fixture1024that includes a bottom part and a side part connected to the bottom part, and the accommodating space of the second fixture1024is defined by a side surface of the side part and an upper surface of the bottom part. In order to accommodate and fixedly place the light-transmissive unit1020in the second fixture1024, a pyrotic adhesive film (not shown) may be adhered to the side surface of the side part and the upper surface of the bottom part, and the light-transmissive unit1020is then disposed on the pyrotic adhesive film, so as to fix the light-transmissive unit1020in the second fixture1024. The second fixture1024may have a second positioning element1025that is located on a top portion of the side part and that may cooperate with the first positioning element1016of the first fixture1015, so that the second fixture1024might be in a positional correspondence with the first fixture1015. In certain embodiments, when the first positioning element1016of the first fixture1015is the positioning spring, the second positioning element1025of the second fixture1024may be a positioning hole. In alternative embodiments, the first positioning element1016of the first fixture1015may be the positioning hole, and the second positioning element1025of the second fixture1024may be the positioning spring.

As shown inFIG.11, the second fixture1024is turned over, so that the light-transmissive unit1020faces the wafer101′, and the first fixture1015and the second fixture1024are aligned and make contact with each other through the first positioning element1016and the second positioning element1025. In such case, the light-transmissive elements102are aligned with the LED chips103disposed on the wafer101′, respectively. In certain embodiments, a central line of each of the light-transmissive elements102that passes through a geometry center of each of the light-transmissive elements102and that extends in the thickness direction (O) overlaps the central line of a corresponding one of the LED chips103.FIG.11also illustrates that the first positioning element1016and the second positioning element1025are in contact with each other, but the light-transmissive unit1020is not in contact with the wafer101′.

Afterwards, as shown inFIG.12, the first fixture1015and the second fixture1024are placed in a vacuum laminating equipment (not shown). The mounting base1021of each of the light-transmissive elements102is in contact with the binder material105′ disposed on the wafer101′, and each of the LED chips103is accommodated in a corresponding one of the cavities104(seeFIG.1), so as to avoid each of the LED chips103being in contact with or damaged by a corresponding one of the light-transmissive regions1022, and to maintain the performance of the LED chips103. During the processes of laminating and vacuuming, since the height of the binder material105′ that fills a corresponding one of the trenches106(seeFIG.4) is higher than that of the second metal layers1012a, the binder material105′ may be squeezed and a portion thereof may move onto the adjacent second metal layers1012a(seeFIG.13).

As shown inFIG.13, an amount of the binder material105′ that fills the trenches 16 becomes less because the portion of the binder material105′ moves onto the adjacent second metal layers1012a. During the vacuuming process, the binder material105′ may continue to move onto and cover the adjacent second metal layers1012a, so as to form the first portions1051aof the first bonding layers1051, so that the light-transmissive unit1020can be tightly connected to the wafer101′ through the first portions1051aof the first bonding layers1051. The remaining portion of the binder material105′ in the trenches 16 is formed into the second portions1051bof the first bonding layers1051. Each of the second portions1051band a corresponding one of the first portions1051amay corporately form a continuous structure, which may further enhance a bonding force between the light-transmissive unit1020and the wafer101′, and improve the airtightness of the LED device100A. During the processes of laminating and vacuuming, the binder material105′ may be baked, which may facilitate flowing of the binder material105′ and the subsequent curing thereof. When the binder material105′ is baked, the pyrotic adhesive film that is adhered to the side surface of the side part of the second fixture1024and the upper surface of the bottom part of the second fixture1024may be decomposed, and an adhesive property of the pyrotic adhesive film may be adversely affected, which then enables the light-transmissive unit1020to be separated from the second fixture1024.

In this embodiment, the portion of the binder material105′ in the trenches 16 moves onto the adjacent second metal layers1012a, and the remaining portion of the binder material105′ becomes less and does not completely fill the trenches 16. In alternative embodiments, by adjusting the amount of the binder material105′, the binder material105′ may uniformly cover the adjacent second metal layers1012a, and completely fill the trenches 16 after the processes of laminating and vacuuming, which may further enhance the airtightness of the LED device100A.

Afterwards, as shown inFIG.14, the first fixture1015and the second fixture1024are removed. For example, first, the vacuuming process is stopped. At this time the second fixture1024may be separated from the first fixture1015by a restoring force of the first positioning element1016(e.g., the positioning spring), thereby obtaining a structure shown inFIG.14. In this embodiment, the portion of the binder material105′ in the trenches 16 moves onto the adjacent second metal layers1012aon the non-functional regions1012without moving to the functional regions1011, thereby preventing the functional regions1011from being polluted.

Therefore, the light-transmissive region1022of each of the light-transmissive elements102of the light-transmissive unit1020is aligned with a corresponding one of the LED chips103, so as to ensure that a shortest distance between the central line of the light-transmissive region1022of each of the light-transmissive elements102and the central line of a corresponding one of the LED chips103is smaller than 100 µm, and the difference of the light exiting angle of light emitted from each of the LED chips103and passing through a geometry center of a corresponding one of the light-transmissive regions1022is smaller than ±3° in a direction perpendicular to the thickness direction (O). In certain embodiments, a distance between a geometry center of each of the light-transmissive elements102and a geometry center of a corresponding one of the LED chips103is smaller than 100 µm.

In step S104, a dicing process is performed on the dicing regions1018of the lighting workpiece in a direction indicated by arrows A1 shown inFIG.14, so as to obtain the LED devices100A (seeFIG.1).

After step S104, each of the LED devices100A has a surrounding surface and cross sections of the surrounding surface are straight lines that extend in the thickness direction (O). In addition, in a direction perpendicular to the thickness direction (O), the light-transmissive element102and the substrate101of each of the LED devices100A have the same width, and in the thickness direction (O), the sidewall of the light-transmissive element102of each of the LED devices100A is aligned with that of the substrate101of each of the LED devices100A. As such, with the abovementioned structure, each of the LED devices100A may be placed in a better location in the vibrator bowl feeder, and the packaging yield of the LED devices100A may be further enhanced.

Referring toFIG.15, a second embodiment of an LED device100B according to the present disclosure is generally similar to the first embodiment, except that, in the second embodiment, the second metal layer1012ais not formed on the non-functional region1012, and the bonding layer105further includes a second bonding layer1052disposed on a sidewall of each of the first bonding layer1051and the mounting base1021. In this embodiment, the first bonding layer1051is disposed between the non-functional region1012and the mounting base1021.

In certain embodiments, the first bonding layer1051and the second bonding layer1052corporately form a continuous structure having an L shape. In the thickness direction (O), the first bonding layer1051may have a thickness (t1) ranging from 50 µm to 150 µm, and the second bonding layer1052may have a thickness (t2) ranging from 200 µm to 400 µm.

In a variation of the second embodiment, as shown inFIG.16, an LED device100C further includes the second metal layer1012aformed on the non-functional region1012of the substrate101, and the first bonding layer1051includes the first portion1051athat is disposed on the second metal layer1012aand the second portion1051bthat is disposed on the non-functional region1012and between the first portion1051aand the second bonding layer1052. In the thickness direction (O), the first portion1051aof the first bonding layer1051may have a thickness (t3) ranging from 35 µm to 50 µm, and the second portion1051bof the first bonding layer1051may have a thickness (t4) ranging from 50 µm to 150 µm. In this variation, the second portion1051bof the first bonding layer1051and the second bonding layer1052corporately form a continuous structure having an L shape.

InFIGS.15and16, by virtue of the continuous structure covering the non-functional region1012and the sidewall of the mounting base1021, and by virtue of the first bonding layer1051being disposed between the mounting base1021and the substrate101, no bubble or gap exists in the LED devices100B,100C, which may significantly improve the airtightness and reliability of the LED devices100B,100C. In addition, the first bonding layer1051and the second bonding layer1052may be made of the same or different materials, such as silica gel, white glue, fluorine resin, etc. The material for forming the first bonding layer1051or the second bonding layer1052may have one or more properties, such as a better adhesion, a certain flowability and a certain reflective function for reflecting light emitted from the LED chip103, which may improve the airtightness of the LED devices100B,100C and extend the service life of the LED devices100B,100C.

As shown inFIGS.15and16, the sidewall of the second bonding layer1052of each of the LED devices100B,100C is aligned with that of the substrate101, which is conducive for each of the LED devices100B,100C to be placed in a better location in the vibrator bowl feeder, and further enhancing a packaging yield of each of the LED devices100B,100C.

In certain embodiments, as shown inFIG.17, the bonding layer105of an LED device100D further includes a fourth bonding layer1054formed on a part of an upper surface of the light-transmissive element102. Specifically, the fourth bonding layer1054is formed on at least a part of an upper surface of the mounting base1021of the light-transmissive element102. It is noted that the fourth bonding layer1054may be formed on the entire upper surface of the mounting base1021. The fourth bonding layer1054and the second bonding layer1052may corporately form a continuous structure. That is to say, the second bonding layer1052and the fourth bonding layer1054may be formed simultaneously. In the thickness direction (O), the fourth bonding layer1054may have a thickness (t5) ranging from 10 µm to 200 µm. By virtue of the bonding layer105covering the mounting base1021of the light-transmissive element102, the airtightness of the LED device100D may be enhanced and the connection between the light-transmissive element102and the substrate101may be increased simultaneously.

In certain embodiments, as shown inFIG.18, the light-transmissive region1022of the light-transmissive element102is a hemi-ellipsoid convex lens having a long axis in the thickness direction (O), and the geometry center of the light-transmissive region1022is located at a position between the top surface103′ of the LED chip103and an inner surface1022′ of the light-transmissive region1022. The light-transmissive element102may have a height (H1) in the thickness direction (O) (i.e., a vertical distance between a topmost point of the light-transmissive element102and a bottommost point of the light-transmissive element102) ranging from 3.00 mm to 3.50 mm, the mounting base1021may have a height (H2) in the thickness direction (O) (i.e., a vertical distance between a topmost point of the mounting base1021and a bottommost point of the mounting base1021) ranging from 0.3 m to 0.7 mm, and the light-transmissive element102may have a width (W) ranging from 2.00 mm to 3.50 mm (e.g., from 3.00 nm to 3.50 nm). As shown inFIG.19, the LED device shown inFIG.18has a light exiting angle of approximately 35°. The light exiting angle of the LED device shown inFIG.18may be adjusted by adjusting the amount of the filler in the cavity104. For example, when the LED device shown inFIG.18includes no filler in the cavity104(i.e., only air or nitrogen is present in the cavity104), the light exiting angle of the LED device shown inFIG.18may range from 25° to 55°. For another example, when the LED device shown inFIG.18includes the filler in the cavity104(e.g., an inorganic gel or other reflective materials), the light exiting angle of the LED device shown inFIG.18may range from 55° to 75°.

Referring toFIG.20, this disclosure also provides a method for manufacturing the variation of the second embodiment of the LED device100C shown inFIG.16, which includes the following consecutive steps S201to S206.FIGS.21to30illustrate intermediate stages of the method for manufacturing the variation of the second embodiment of the LED device100C.

Steps201and202(seeFIG.21) are the same as steps S101and S102of the aforesaid method shown inFIG.3, respectively, and therefore the details thereof are omitted for the sake of brevity.

Step S203(seeFIGS.22to27) is generally similar to step S103, except for the following differences.

As shown inFIG.22, the first portions1051aof the first bonding layers1051of the bonding layers105are formed on the second metal layers1012a, respectively, by directly applying a binder material on the second metal layers1012a. The thickness of each of the first portions1051amay range from 35 µm to 100 µm, such as approximately 50 µm. After this step, the light-transmissive unit1020is connected to the wafer101′ through the first portions1051a, and covers the LED chips103with the first and second fixtures1015,1024.

In certain embodiments, step S203may be performed in the same way as step S103. That is to say, the binder material105′ fills the trenches106(seeFIG.28), and is subsequently formed into the first portions1051athat are respectively disposed on the second metal layers1012a, and the second portions1051bthat are respectively disposed on the non-functional regions1012of the wafer101′ and that are respectively located outside the second metal layers1012a.

In step S204, a plurality of through holes1023are formed and are in correspondence with the dicing regions1018, respectively (seeFIG.29).

As shown inFIG.29, in this step, a first dicing process is performed on the light-transmissive unit1020along a dicing direction indicated by arrows A11, so as to form the through holes1023. The through holes1023are spatially communicated with the trenches106, respectively.

In step S205, a plurality of the second bonding layers1052are formed in the through holes1023, respectively.

As shown inFIG.30, in this step, a bonding material (i.e., a silica gel) fills the through holes1023and the trenches106(seeFIG.29), and is subsequently baked then cured so as to be formed into the second bonding layers1052. In addition, since the trenches106in this embodiment are not filled with the first bonding layers1051, the bonding material may flow into the trenches106between the mounting bases1021and the wafer101′, forming the second portions1051bof the first bonding layers1051.

In step S206, a second dicing process is performed on the dicing regions1018of the wafer101′, so as to obtain the LED devices100C.

Specifically, the second dicing process is performed on the second bonding layers1052along a dicing direction indicated by arrows A12(seeFIG.30), thereby obtaining the LED devices100C. In a direction perpendicular to the dicing directions (indicated by the arrows A11shown inFIG.29and the arrows A12shown inFIG.30), a width of each of second dicing lines in the second dicing process is smaller than that of a respective one of first dicing lines in the first dicing process, so that a portion of each of the second bonding layers1052is removed, and a residual portion of each of the second bonding layers1052remains on the sidewall of a corresponding one of the mounting bases1021and the sidewall of a corresponding one of the second portions1051bof the first bonding layers1051and may have a certain width. In certain embodiments, the width of each of the first dicing lines may be two times the width of a respective one of the second dicing lines, and the width of the residual portion of each of the second bonding layers1052may be half of the width of a corresponding one of the second dicing lines.

In certain embodiments, as shown inFIG.31, in step S103or S203, the light-transmissive elements102of the light-transmissive unit1020may be connected with or separated from each other.

In certain embodiments, as shown inFIGS.32and33, in step S203, the first fixture1015includes a plurality of the first positioning elements1016(5 of the first positioning elements1016(e.g., the positioning springs) as shown inFIG.32), and the number of the second positioning element1025(e.g., the positioning hole) of the second fixture1024is in correspondence with the number of the first positioning element1016. In such case, the second fixture1024has a plurality of the accommodating spaces, and the light-transmissive elements102that are separately formed are placed in the accommodating spaces of the second fixture1024, respectively.

When the light-transmissive elements102of the light-transmissive unit1020are separated from each other (seeFIG.31) and respectively placed in the accommodating spaces of the second fixture1024(seeFIG.33) in step S203, step S204may be omitted.

Referring toFIG.34, a third embodiment of an LED device100E according to the present disclosure is generally similar to the variation of the second embodiment shown inFIG.16, except that, in the third embodiment, the bonding layer105further includes a third bonding layer1053disposed on at least a part of the sidewall of the substrate101. In this embodiment, the third bonding layer1053, the first bonding layer1051, and the second bonding layer1052corporately form a continuous structure having a T shape. In a first variation of the third embodiment, as shown inFIG.35, the third bonding layer1053is formed to completely cover the sidewall of the substrate101.

As shown inFIG.34, in this embodiment, the sidewall of the substrate101is formed with an indented platform1017, and the third bonding layer1053is disposed on the indented platform1017and is connected to the second bonding layer1052. By virtue of the continuous structure of the bonding layer105that is disposed on the sidewall of the mounting base1021and the at least a part of the sidewall of the substrate101, the airtightness of the LED device100E may be further enhanced.

A method for manufacturing the third embodiment of the LED device100E is generally similar to the aforesaid method shown inFIG.20except for the following differences.

As shown inFIG.36, after formation of the through holes1023and before the second dicing process, the first dicing process is continually performed on the wafer101′ along the dicing direction indicated by the arrows A11, so as to form a plurality of recesses1014in the wafer101′. The recesses1014are respectively located in the dicing regions1018(not shown) of the wafer101′, and are spatially communicated with the through holes1023, respectively. Afterwards, as shown inFIG.37, a binder material fills the recesses1014and the through holes1023, so that a plurality of the third bonding layers1053are respectively formed in the recesses1014, and a plurality of the second bonding layers1052are respectively formed in the through holes1023. Then, the second dicing process is performed along the dicing direction indicated by the arrows A12, so as to obtain the LED devices100E shown inFIG.34. The side surfaces of the second and third bonding layers1052,1053are flush with the side surface of the substrate101in the thickness direction (O).

In certain embodiments, as shown inFIG.38, when the light-transmissive elements102of the light-transmissive unit1020are independently disposed on the wafer101′ and are spaced apart from each other by the through holes1023(seeFIG.31), the structure shown inFIG.31is subjected to a dicing process along the dicing direction indicated by arrows A13, so as to form the recesses1014in the wafer101′.

The recesses1014may have a depth ranging from ⅓ to ⅔ of a thickness of the wafer101′, so as to maintain a structural strength of the wafer101′ while forming the recesses1014.

As shown inFIG.34, the thickness (t1) of the first bonding layer1051in the thickness direction (O) may range from 35 µm to 150 µm. The thickness of the first portion1051ain the thickness direction (O) may range from 35 µm to 50 µm, and the thickness of the second portion1051bin the thickness direction (O) may range from 50 µm to 150 µm.The thickness (t2) of the second bonding layer1052may range from 200 µm to 400 µm.A thickness (t3) of the third bonding layer1053may range from ⅓ to ⅔ of the thickness of the substrate101.

As shown inFIG.35, the third bonding layer1053is completely formed on and covers the sidewall of the substrate101. In this variation, the bonding layer105that includes the first, second, and third bonding layers1051,1052,1053covers the sidewall of the light-transmissive element102and the sidewall of the substrate101, which may further enhance the airtightness of the LED device100F.

A method for manufacturing the first variation of the third embodiment of the LED device100F shown inFIG.35is generally similar to the method for manufacturing the third embodiment of the LED device100E except for the following differences. Specifically, in the method for manufacturing the first variation of the third embodiment of the LED device100F, after the formation of the through holes1023, the first dicing process is continually performed on the wafer101′ that is fixedly placed in a fixture (e.g., the wafer101′ is adhered to an inner wall of the fixture through an adhesive film) so as to form the recesses1014that penetrate the wafer101′ in the thickness direction (O). After formation of the recesses1014, the third bonding layers1053are formed in the recesses1014, respectively. Afterwards, the second dicing process is performed, so as to obtain a plurality of the LED devices100F.

In a second variation of the third embodiment, as shown inFIG.39, the bonding layer105of an LED device100G further includes a fourth bonding layer1054formed on a part of the upper surface of the light-transmissive element102. Specifically, the fourth bonding layer1054may be formed on at least a part of the upper surface of the mounting base1021of the light-transmissive element102. In this variation, the fourth bonding layer1054is formed on a part of the upper surface of the mounting base1021of the light-transmissive element102. It is noted that the fourth bonding layer1054may be formed on the entire upper surface of the mounting base1021of the light-transmissive element102. The fourth bonding layer1054and the second bonding layer1052may corporately form a continuous structure. That is to say, the second bonding layer1052and the fourth bonding layer1054may be formed simultaneously. In the thickness direction (O), the thickness (t5) of the fourth bonding layer1054may range from 10 µm to 200 µm. By virtue of the bonding layer105covering the light-transmissive element102, the airtightness of the LED device100G may be further enhanced and the connection between the light-transmissive element102and the substrate101may be increased simultaneously.

Referring toFIG.40, a fourth embodiment of an LED device200A according to the present disclosure is generally similar to the second embodiment shown inFIG.15, except that, in the fourth embodiment, the substrate201is formed with a receiving space, and thus has a cup structure.

In this embodiment, the substrate201includes a bottom portion2010′, and a surrounding portion2010. The surrounding portion2010is connected to and extends upwardly from the bottom portion2010′, so as to form the receiving space. An upper surface of the bottom portion2010′ of the substrate201has the functional region2011, and an upper surface of the surrounding portion2010has the non-functional region2012and the dicing region2018. In certain embodiments, a metal layer (not shown) may be formed on the functional region2011, and may have a thickness ranging from 30 µm to 100 µm, such as 50 µm.

In this embodiment, by virtue of the bonding layer205having the L-shaped structure, the airtightness and reliability of the LED device200A may be enhanced.

In a variation of the fourth embodiment, as shown inFIG.41, the light-transmissive element102has a lens structure, and the bottom surface 102a (proximate to the LED chip203) of the light-transmissive region1022is flush with the bottom surface of the mounting base1021. In this variation, the cavity204has a relatively smaller size as compared with the cavity104shown inFIG.40.

With the structural design of the light-transmissive element102shown inFIG.41, a distance between the light-transmissive element102and the LED chip203is reduced, so that the light-transmissive element102may provide better transmittance, which is conducive for enhancing the luminous efficiency of the LED device200B.

Referring toFIG.42, a fifth embodiment of an LED device200C according to the present disclosure is generally similar to the fourth embodiment shown inFIG.40, except that, in the fifth embodiment, the bonding layer205further includes a third bonding layer2053disposed on at least a part of the sidewall of the substrate201. In this embodiment, the third bonding layer2053, the first bonding layer2051, and the second bonding layer2052corporately form a continuous structure having a T shape. In certain embodiments, the third bonding layer2053may cover the entire sidewall of the substrate201.

By virtue of the aforesaid bonding layer205having the T-shaped structure, the airtightness and reliability of the LED device200C may be enhanced.

In a variation of the fifth embodiment, as shown inFIG.43, the light-transmissive element102has the lens structure, and the bottom surface 102a (proximate to the LED chip203) of the light-transmissive region1022is flush with the bottom surface of the mounting base1021. In this variation, the cavity204has a relatively smaller size as compared to the size of the cavity204shown inFIG.42. With the structural design of the light-transmissive element102, the distance between the light-transmissive element102and the LED chip203is reduced, so that the light-transmissive element102may provide better transmittance, which is conducive for enhancing the luminous efficiency of the LED device200D. In certain embodiments, in this variation, the third bonding layer2053may cover the entire sidewall of the substrate201.

Referring toFIG.44, a sixth embodiment of an LED device200E according to the present disclosure is generally similar to the fourth embodiment shown inFIG.40, except that, in the sixth embodiment, the bonding layer205only has the first bonding layer2051, and the light-transmissive element202has a plate structure. In this embodiment, the sidewall of the light-transmissive element202is aligned with the sidewall of the bonding layer205and the sidewall of the substrate201in the thickness direction (O), which is conducive for the LED device200E to be placed in a better location in the vibrator bowl feeder, and further enhancing a packaging yield of the LED device200E.

In a variation of the sixth embodiment, as shown inFIG.45, the bonding layer205further includes the second bonding layer2052that is disposed on the upper surface of the surrounding portion2010of the substrate201and that covers the sidewall of the light-transmissive element202. The light-transmissive element202may be made of one of a flat quartz glass and a plastic material. In this variation, the light-transmissive element202is made of a quartz glass. The thickness of the light-transmissive element202is smaller than that of each of the LED chip203and the surrounding portion2010of the substrate201. In certain embodiments, the thickness of the light-transmissive element202may be approximately 350 µm, the thickness of the LED chip203may be approximately 500 µm, and the thickness of the surrounding portion2010of the substrate201may be greater than 1000 µm. The mounting base2021is connected to the upper surface of the surrounding portion2010of the substrate201through the bonding layer205, and the light-transmissive region2022simultaneously covers the cup structure of the substrate201and the LED chip203. In this variation, the first bonding layer2051and the second bonding layer2052corporately form a continuous structure that has an L shape and that covers the sidewall of the light-transmissive element202, which may significantly enhance the connection between the light-transmissive element202and the substrate201, and improve the airtightness of the LED device200F. In this variation, the thickness of the first bonding layer2051is smaller than that of the second bonding layer2052. The thickness of the first bonding layer2051may range from 35 µm to 150 µm, and the thickness of the second bonding layer2052may range from 200 µm to 400 µm. In addition, the sidewall of the second bonding layer2052is aligned with the sidewall of the substrate201in the thickness direction (O), which is conducive for the LED device200F to be placed in a better location in the vibrator bowl feeder and for improving a packaging yield of the LED device200F, while enhancing the airtightness of the LED device200F.

A method for manufacturing the sixth embodiment of the LED device200E includes the following consecutive steps S201to S204that are generally similar to the consecutive steps S101to S104of the aforesaid method shown inFIG.3, except for the following differences.FIGS.46to48illustrate intermediate stages of the method for manufacturing the sixth embodiment of the LED device200E.

As shown inFIG.46, in step S201, the wafer201′ having a plurality of the receiving spaces is provided. The wafer201′ has the first surface and the second surface opposite to the first surface. The first surface is shaped to form the receiving spaces, and has the functional regions2011respectively in the receiving spaces and the non-functional regions2012among the receiving spaces. The electrode pads2013are disposed on the second surface. The metal layer (not shown) may be formed on the functional regions2011by deposition and etching. The dicing regions2018are located among the receiving spaces and overlap the non-functional regions2012.

As shown inFIGS.47and48, in step S203, the bonding layers205are formed on the non-functional regions2012(seeFIG.47). The bonding layers205are made of a binder material having a certain flowability, and the thickness of the bonding layer205is smaller than 50 µm. After formation of the bonding layers205, the light-transmissive unit2020is connected to the wafer201′, so as to obtain a lighting workpiece (seeFIG.48). Afterwards, step204(i.e., the dicing process) is performed, so as to obtain a plurality of the LED devices200E (seeFIG.44).

A method for manufacturing the variation of the sixth embodiment of the LED device200F shown inFIG.45includes the consecutive steps S301to S306, wherein steps S301to S303are the same as the steps S201to S203of the aforesaid method for manufacturing the sixth embodiment of the LED device200E.FIGS.49and50illustrate intermediate stages of the method for manufacturing the variation of the sixth embodiment of the LED device200F.

As shown inFIG.49, in step S304, a plurality of the through holes2023are formed in the light-transmissive unit2020and are located above the dicing regions2018, respectively.

In this step, the first dicing process is performed on the structure shown inFIG.48along the dicing direction indicated by arrows A21shown inFIG.49, so as to form the through holes2023.

As shown inFIG.50, in step S305, a plurality of the second bonding layers2052are formed in the through holes2023, respectively. Each of the second bonding layers2052may cooperate with a corresponding one of the first bonding layers2051to form a continuous structure.

In step S306, the second dicing process is performed on the second bonding layers1052along the dicing direction indicated by arrows A22shown inFIG.50, so as to obtain a plurality of the LED devices200F.

In this step, in a direction perpendicular to the dicing direction (i.e., indicated by the arrows A21and A22respectively shown inFIGS.49and50), a width of each of second dicing lines in the second dicing process is smaller than that of a respective one of first dicing lines in the first dicing process, so that a portion of each of the second bonding layers2052is removed, and a residual portion of each of the second layers2052remains on the light-transmissive unit2020. In certain embodiments, the width of each of the first dicing lines may be two times the width of a respective one of the second dicing lines, and the width of each of the second bonding layers2052may be two times the width of a corresponding one of the second dicing lines.

In certain embodiments, in step S303, the light-transmissive unit2020includes a plurality of the light-transmissive elements202that are separated from each other. Each of the light-transmissive elements202is made of quartz glass. The light-transmissive elements202may be obtained by dicing the light-transmissive unit2020, or may be formed separately. As shown inFIG.51, in step S303, the light-transmissive elements202are connected to the wafer201′, and are separated by the through holes2023. In such case, step S304(i.e., the first dicing process) can be omitted. Afterwards, steps S305and S306are sequentially performed, so as to obtain the LED devices200E (seeFIG.44).

Referring toFIG.52, a seventh embodiment of an LED device200G according to the present disclosure is generally similar to the variation of the sixth embodiment shown inFIG.45, except that, in the seventh embodiment, the bonding layer205further includes a third bonding layer2053. In this embodiment, the third bonding layer2053, the first bonding layer2051, and the second bonding layer2052may corporately form a T-shaped structure.

As shown inFIG.52, an outer sidewall of the surrounding portion2010of the substrate201is formed with an indented platform2017, and the third bonding layer2053is formed on the indented platform2017and is connected to the first bonding layer2051and the second bonding layer2052. In this embodiment, the bonding layer205covers the sidewall of the light-transmissive element202and a part of the sidewall of the substrate201, thereby enhancing the airtightness of the LED device200G.

Referring toFIGS.53and54, a method for manufacturing the seventh embodiment is generally similar to the aforesaid method for manufacturing the variation of the sixth embodiment, except for the following differences.

As shown inFIG.53, after formation of the through holes2023, the first dicing process is continually performed along the dicing direction indicated by arrows A23, so as to form the recesses2014located in the dicing regions2018of the wafer201′. The recesses2014are spatially communicated with the through holes2023, respectively. Afterwards, as shown inFIG.54, a binder material fills the recesses2014and the through holes2023, so as to form the third bonding layers2053and the second bonding layers2052. Then, the second dicing process is performed on the structure shown inFIG.54along the dicing direction indicated by arrows A24, so as to obtain a plurality of the LED devices200G (seeFIG.52).

In certain embodiments, as shown inFIG.55, when the light-transmissive elements202of the light-transmissive unit2020are independently disposed on the wafer201′ and are spaced apart from each other by the through hole2023, dicing the light-transmissive unit2020is omitted. In such case, the first dicing process is performed only on the wafer201′ along the dicing direction indicated by arrows A25so as to form the recesses2014in the dicing regions2018of the wafer201′. In certain embodiments, a depth of the recesses2014may be about one half of the thickness of the wafer201′ in the dicing direction or smaller than one half of the thickness of the wafer201′, so as to maintain the structural strength of the wafer201′ while forming the recesses2014.

After the formation of the recesses2014, the subsequent steps (i.e., formation of the third and second bonding layers2053,2052and the second dicing process) are performed, thereby obtaining the LED devices200G.

In a variation of the seventh embodiment, as shown inFIG.56, the third bonding layer2053may be formed to completely cover the sidewall of the surrounding portion2010of the substrate201. In this variation, the bonding layer205that includes the first, second, and third bonding layers2051,2052,2053covers the sidewall of the light-transmissive element202and the sidewall of the substrate201, so as to further enhance the airtightness of the LED device200H.

A method for manufacturing the variation of the seventh embodiment of the LED device200H is generally similar to the aforesaid method for manufacturing the seventh embodiment of the LED device200G, except that, in the method for manufacturing the variation of the seventh embodiment of the LED device200H, the recesses2014penetrate the wafer201′ that is fixedly placed in a fixture (e.g., the wafer201′ is adhered to an inner wall of the fixture through an adhesive film), and a binder material (not shown) subsequently fills the recesses2014, so as to form the third bonding layers2053in the recesses2014, respectively.

Referring toFIG.57, an eighth embodiment of an LED device2001according to the present disclosure is generally similar to the variation of the sixth embodiment shown inFIG.45, except for the following differences. Specifically, the surrounding portion2010of the substrate201is formed with an indentation207that is indented from the upper surface of the surrounding portion2010toward the bottom portion2010′. The indentation207is located proximate and is spatially communicated with the receiving space. The indentation207is defined by a base surface2071and a peripheral surface2072interconnected the base surface2071and the upper surface of the surrounding portion2010. The first bonding layer2051of the bonding layer205is located between the base surface2071and the mounting base2021of the light-transmissive element202. The second bonding layer2052of the bonding layer205is located between the peripheral surface2072and the sidewall of the light-transmissive element202. In this embodiment, the first bonding layer2051and the second bonding layer2052may corporately form a continuous structure that has an L shape and that partially covers the light-transmissive element202, thereby enhancing the connection between the light-transmissive element202and the substrate201, and the airtightness of the LED device2001.

In a first variation of the eighth embodiment, as shown inFIG.58, the second bonding layer2052is not only located between the peripheral surface2072and the sidewall of the light-transmissive element202, but also extends onto a part of the upper surface of the surrounding portion2010. The first bonding layer2051and the second bonding layer2052corporately form a continuous structure having a Z shape. In this variation, a contact area among the second bonding layer2052, the substrate201and the light-transmissive element202increases, thereby further enhancing the connection between the substrate201and the light-transmissive element202, and the airtightness of the LED device200J.

In a second variation of the eighth embodiment, as shown inFIG.59, the second bonding layer2052extends onto and is formed on the entire upper surface of the surrounding portion2010.

In a third variation of the eighth embodiment, as shown inFIG.60, the second bonding layer2052extends onto and is formed on the entire upper surface of the surrounding portion2010, and an upper surface of the second bonding layer2052is flush with the upper surface of the light-transmissive element202, so that the second bonding layer2052completely covers the sidewall of the light-transmissive element202. In certain embodiments, the upper surface of the second bonding layer2052may be located at a level higher than that of the upper surface of the light-transmissive element202, and may extend onto and be formed on a part of the upper surface of the light-transmissive element202, so as to partially enclose the light-transmissive element202.

To determine the airtightness of the LED device according to this disclosure, samples of three LED devices100A,100C,100E of this disclosure are prepared.

The samples of three LED devices100A,100C,100E (respectively shown inFIGS.1,16and34) are placed in a helium gas leakage tester and are then subjected to a helium gas leakage test. The result is shown inFIG.61. As shown inFIG.61, compared with a conventional LED device having a structure similar to the structure shown inFIG.1(w/o the second portion1051bof the first bonding layer1051), the helium gas leakage rate of the samples of the LED device100A  obviously decreases. The helium gas leakage rate of the conventional LED device is greater than 9.0×10-9Pa•m2/s. The helium gas leakage rate of each of the samples of the LED devices100A,100C,100E is obviously lower than 9.0×10-9Pa•m2/s, and the helium gas leakage rate of most of the samples of the LED devices100A,100C,100E is 6.0×10-9Pa•m2/s. Therefore, compared with the conventional LED device, the airtightness and reliability of the LED devices100A,100C,100E of this disclosure obviously increase.

The helium gas leakage rate of the samples of the LED devices100C,100E is lower than that of the samples of the LED device100A. Specifically, the helium gas leakage rate of the samples of the LED device100E is lower than 3.5×10-9Pa•m2/s, and the helium gas leakage rate of 80% of a number of the samples of the LED device100C is lower than 5.0×10-9Pa•m2/s. In view of above, the LED devices having the L-shaped bonding layer105(i.e., the LED device100C) or the T-shaped bonding layer105(i.e., the LED device100E) might have increased airtightness and reliability.