CN108598246A - A kind of SMD-UV-LED of vacuum tight encapsulation - Google Patents

Abstract

The invention discloses a vacuum-sealed SMD-UV-LED, which comprises a base plate, four groups of metal frames are symmetrically installed around the top edge of the base plate, and the bottom of the metal frame and the edge top of the base plate are arranged The first sealing layer, the top of the metal frame is connected with the bottom edge around the glass window, and the second sealing layer is arranged between the top of the metal frame and the bottom edge around the glass window, the first sealing Both the first layer and the second sealing layer are sealed and packaged, and the substrate, metal frame and glass light window form a relatively sealed cavity, which can realize product design for mass production; low cost, miniaturization, surface mount standard Components; Solve the problem of rapid degradation of light output performance of UV LEDs in non-hermetic packages after hundreds of hours of operation due to the failure of the sealing level to meet the requirements; products with TEC semiconductor cooling structures to meet large Power chips have extremely high heat dissipation requirements and are suitable for promotion and popularization.

Description

SMD-UV-LED in a vacuum airtight package

technical field

The invention belongs to the technical field of optoelectronic packaging, and belongs to the field of surface mount (SMD) hermetic packaging of ultraviolet light-emitting diodes (UV-LED) with high light efficiency, high reliability and high thermal conductivity for special applications, and specifically relates to a vacuum airtight package SMD-UV-LEDs.

Background technique

Ultraviolet light-emitting diodes are divided into UVC deep ultraviolet (190nm~280nm), near ultraviolet UVB (280~380nm) and ultraviolet UVA (380~420nm) in terms of wavelength, each has its own characteristics and application fields, such as UVA, UVB in anti-counterfeiting , Light curing, UVC is widely used in the field of disinfection.

The traditional ultraviolet generator is usually a fluorescent tube, which generates ultraviolet light under the action of cathode rays through the substance coated in the sealed glass tube, which has the advantages of simple process and low cost. However, the inner filling material usually contains heavy metal substances such as mercury (Hg), and it has been clearly banned from use in a few years. Moreover, the fluorescent efficiency is low, and it is difficult to miniaturize. Therefore, in recent years, a brand-new ultraviolet light-emitting diode chip has been developed and packaged into a small sticker component, which gradually appears on the market. For this reason, we propose a vacuum-sealed SMD-UV-LED to solve the problems existing in the prior art.

Contents of the invention

The purpose of the present invention is to provide a SMD-UV-LED in vacuum airtight packaging, a product structure scheme proposed for the miniaturized SMD packaging of ultraviolet LEDs that require airtight packaging, especially ultraviolet UV-LEDs. For the special requirements of light-transmitting components, the special requirements of the chip for the environment, and the characteristics of the chip's low light-emitting/heating ratio, a kind of aluminum nitride heat-dissipating substrate base with TEC (thermal energy conversion structure) is proposed, which can meet the requirements of ultraviolet transmission. The quartz glass airtight light window is eutectic with the chip and the TEC cold end, and after the wire bonding (WIRE BOND) is completed, the quartz glass light window is passed through the process of laser, parallel sealing welding or fusion sealing to complete the reliability of UV-LED. sealed package.

To achieve the above object, the present invention adopts the following technical solutions:

A vacuum-sealed SMD-UV-LED, including a substrate, four groups of metal frames are symmetrically installed around the top edge of the substrate, and a first sealing layer is provided between the bottom of the metal frame and the edge top of the substrate , the top of the metal frame is connected with the bottom edge around the glass window, and a second sealing layer is arranged between the top of the metal frame and the bottom edge around the glass window, the first sealing layer and the second The sealing layers are all sealed and packaged, the substrate, the metal frame and the glass light window form a relatively sealed cavity, the bottom of the glass light window is fixedly installed with a semiconductor refrigerator, and the top of the semiconductor refrigerator is provided A gold-tin solder sheet, and a chip is installed on the gold-tin solder sheet, two groups of second electrodes are mounted symmetrically on the top of the substrate, two groups of first electrodes are mounted symmetrically on the bottom of the substrate, and two groups of first electrodes are mounted on the bottom of the substrate symmetrically. There are electrical conduction holes for connecting the first electrode and the second electrode to realize the conduction between the upper and lower points, and the electrical conduction holes are arranged inside or at the edge of the substrate, and the top ends of a group of the second electrodes are electrically connected by binding gold wires. One end of the second electrode is electrically connected to one end of the chip electrode, and the top end of the second electrode of the other group is electrically connected to one end of the electrode of the semiconductor refrigerator by binding gold wires.

Preferably, the substrate is an aluminum nitride substrate, the specification is SMD, made of aluminum nitride ceramic material, and the thermal conductivity of the aluminum nitride ceramic is 170-230W/mK.

Preferably, the semiconductor refrigerator further includes a TEC cold end and a TEC hot end, the TEC cold end is located at the top of the semiconductor refrigerator, and the TEC hot end is located at the bottom of the semiconductor refrigerator.

Preferably, the chip can be an ultraviolet UVA-LED, UVB-LED, UVC-LED, FP, DFB, VCSEL and other chips, and the chip is packaged in a miniaturized SMD.

The present invention also provides a method for preparing a vacuum-sealed SMD-UV-LED, comprising the following steps:

S1. The substrate base adopts aluminum nitride (ALN+TEC+metallization) substrate base, the specification is SMD6060, and it is cleaned and dried for later use;

S2. Chip: 60mW UV-LED chip with a wavelength of 190-280nm and a gold wire diameter of 30um for use;

S3. The glass light window is made of 60*60mm square piece of quartz glass with a thickness of 0.3mm, and the bottom is made of metallized and fused alloy-tin alloy solder. The solder area is a gold-tin alloy frame with a width of 0.5 mm and a thickness of 10 microns around the quartz square;

S4. Laser drilling of aluminum nitride substrate: pre-drilling according to the circuit design, that is, electrical conduction holes;

S5. The chip is bonded through 300-degree eutectic welding and TEC cold end, and connected to the two electrodes of the substrate seat through gold wire. The TEC supply electrode is also connected to the other two electrodes on the substrate base with gold wires to complete the chip fixing and wire bonding process;

S6. Place the materials that have completed the S5 link on the graphite fixture, with the chip facing up, place the 60*60mm quartz glass light window and the side with solder on the surface metallized ceramic substrate base, and pass through the graphite fixture. Positioning, placed in a nitrogen (or argon) shielded sealing furnace;

S7. Technical index test: The ultraviolet UV-LED prepared by the present invention is compared with the currently used organic glue-bonded product and the hermetic packaging product without TEC structure for relative performance and reliability.

Preferably, the temperature setting intervals inside the sealing furnace in S6 are 100-120°C; 200-250°C; 280-300°C; 150-200°C; 30-50°C, one or more groups .

Technical effect and advantage of the present invention: the SMD-UV-LED of a kind of vacuum airtight packing that the present invention proposes, compared with prior art,

1. Product design that can realize mass production;

2. Low-cost, miniaturized, surface-mounted standard components, such as SMD3535, SMD3830, SMD6060, etc.;

3. Solved the problem of rapid degradation of light output performance of deep ultraviolet LEDs with non-hermetic packaging after hundreds of hours of operation due to the failure of the sealing level to meet the requirements;

4. Products with semiconductor refrigeration structure with TEC to meet the extremely high heat dissipation requirements of high-power chips;

5. The product structure design can be adapted to various packaging processes, such as laser welding, parallel sealing welding, low-temperature brazing and other processes, and the product structure of various quartz lenses or light windows can be freely combined.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention;

Fig. 2 is a side sectional view of the substrate of the present invention

Fig. 3 is the top view of structure of the present invention;

Fig. 4 is a schematic structural diagram of a semiconductor refrigerator of the present invention;

Fig. 5 is the preparation process flowchart of low temperature sealing welding method of the present invention;

Fig. 6 is a flow chart of the preparation process of the laser or parallel sealing welding method of the present invention.

In the figure: 1 substrate, 101 electrical conduction hole, 2 metal frame, 3 first sealing layer, 4 second sealing layer, 5 glass light window, 6 first electrode, 7 second electrode, 8 bonded gold wire, 9 chip , 10 semiconductor refrigerator, 1001TEC cold end, 1002TEC hot end, 1003 gold tin solder sheet, 11 cavity.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. The specific embodiments described here are only used to explain the present invention, not to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example:

The present invention provides that Fig. 1～4 and Fig. 5 are the preparation process flowchart of low-temperature sealing welding method of the present invention; Fig. 6 is shown in the preparation process flow chart of laser or parallel sealing welding method of the present invention:

A vacuum airtight SMD-UV-LED, including a substrate 1, four groups of metal frames 2 are symmetrically installed around the top edge of the substrate 1, and the bottom of the metal frame 2 and the edge top of the substrate 1 are provided. There is a first sealing layer 3, the top of the metal frame 2 is connected to the bottom edge around the glass window 5, and a second sealing layer is arranged between the top of the metal frame 2 and the bottom edge around the glass window 5 4. Both the first sealing layer 3 and the second sealing layer 4 are hermetically sealed, the substrate 1, the metal frame 2 and the glass light window 5 form a relatively sealed cavity 11, and the inner bottom of the glass light window 5 A semiconductor refrigerator 10 is fixedly installed, and a gold-tin solder sheet 1003 is arranged on the top of the semiconductor refrigerator 10, and a chip 9 is installed on the gold-tin solder sheet 1003, and two groups of The second electrode 7, two sets of first electrodes 6 are symmetrically installed on the bottom of the substrate 1, and the substrate 1 is provided with an electrical connection for connecting the first electrode 6 and the second electrode 7 to realize the upper and lower point conduction. hole 101, and the electrical conduction hole 101 is arranged inside or at the edge of the substrate 1, one end of the top of one group of the second electrodes 7 is electrically connected to one end of the electrode of the chip 9 by binding gold wires 8, and the other group of the One end of the top of the second electrode 7 is electrically connected to one end of the electrode of the semiconductor refrigerator 10 by binding a gold wire 8 .

Preferably, the substrate 1 is an aluminum nitride substrate, the specification is SMD6060, made of aluminum nitride ceramic material, and the thermal conductivity of the aluminum nitride ceramic is 170-230 W/mK.

By adopting the above technical solution, the substrate 1 is an aluminum nitride substrate, the specification is SMD6060, and it is made of aluminum nitride ceramic material, and the thermal conductivity of the aluminum nitride ceramic is 170-230W/mK, that is, a ceramic with high thermal conductivity. The material is fired at about 1700°C by aluminum nitride powder.

Preferably, the semiconductor refrigerator 10 further includes a TEC cold end portion 1001 and a TEC hot end portion 1002, the TEC cold end portion 1001 is located at the top of the semiconductor refrigerator 10, and the TEC hot end portion 1002 is located at the top of the semiconductor refrigerator. The bottom end of the refrigerator 10.

By adopting the above technical solution, the semiconductor refrigerator 10 further includes a TEC cold end portion 1001 and a TEC hot end portion 1002, the TEC cold end portion 1001 is located at the top of the semiconductor refrigerator 10, and the TEC hot end portion 1002 Located at the bottom of the semiconductor refrigerator 10 , it is a semiconductor refrigeration chip manufactured by using the Peltier effect. In the present invention, the TEC cold end 1001 is bonded to the optoelectronic chip 9 through the gold-tin solder sheet 1003 .

Preferably, the chip 9 can be an ultraviolet UVA-LED, UVB-LED, UVC-LED, FP, DFB, VCSEL and other chips, and the chip 9 is packaged in a miniaturized SMD.

By adopting the above technical scheme, the chip 9 can be ultraviolet UVA-LED, UVB-LED, UVC-LED, FP, DFB, VCSEL and other chips, and the chip 9 is packaged in a miniaturized SMD, and the chip 9 has high and low temperature impact resistance Strong, improve the reliability, stability and service life of LED products.

Working principle: Firstly, the substrate base adopts aluminum nitride (ALN+TEC+metallization) substrate base, the specification is SMD6060, and it is cleaned and dried for standby; chip: 60mW UV-LED chip is used, the wavelength is 190-280nm, and the diameter of the gold wire is 30um Standby; the glass light window is made of 60*60 mm square piece of quartz glass with a thickness of 0.3 mm, and the bottom is metallized and soldered with alloy-tin alloy. The solder area is a quartz square, surrounded by a gold-tin alloy frame with a width of 0.5 mm and a thickness of 10 microns; laser drilling of the aluminum nitride substrate: pre-drilled according to the circuit design, that is, an electrical conduction hole; the chip passes through 300 degrees Eutectic soldering and TEC cold end bonding are connected by gold wires to the two electrodes of the substrate holder. The TEC supply electrode is also connected with the other two electrodes on the substrate base with gold wires to complete the chip fixing and wire binding process; the materials that have completed the above links are placed on the graphite fixture with the chip facing up, and the 60*60 mm quartz glass Light window, one side with soldering material is placed on the surface metallized ceramic substrate base, positioned by graphite fixtures, placed in the sealing furnace of nitrogen (or argon) protection; technical index test: the ultraviolet ray prepared by the present invention The performance and reliability of UV-LED are compared with the currently used organic adhesive bonding products and hermetic packaging products without TEC structure.

The present invention provides that the product is placed in a nitrogen (or argon) protected sealing furnace, and the sealing welding process is completed according to the following parameters, as shown in Table 1 below:

The present invention also provides the prepared ultraviolet UV-LED to conduct comparative tests with the currently used organic adhesive products and the hermetic packaging products without TEC structure and reliability, and obtain the following results, as shown in Table 2 Show:

What the present invention emphasizes is the idea of a process method and structure and the improvement in product performance brought about thereby, and is not limited to a certain specific material, shape and size and what process equipment is used, as long as it is similar to the idea of the present invention The shapes and methods should also be regarded as included in the scope of the present invention.

Finally, it should be noted that: the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it still It is possible to modify the technical solutions recorded in the foregoing embodiments, or to perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. within the spirit and principles of the present invention shall be included in the within the protection scope of the present invention.

Claims (6)

1. a kind of SMD-UV-LED of vacuum tight encapsulation, including substrate (1), it is characterised in that：The top sides of the substrate (1) Edge surrounding is symmetrically equipped with four groups of metal frameworks (2), and the edge top of the bottom of metal framework (2) and substrate (1) it Between be equipped with the first sealant (3), the top of the metal framework (2) connect at the surrounding bottom margin of glass optical window (5), And the second sealant (4) is equipped between the top and the edge bottom of glass optical window (5) of metal framework (2), described first Sealant (3) and the second sealant (4) are all made of hermetically sealed, the substrate (1), metal framework (2) and glass optical window (5) shape At the cavity (11) of opposing seal, glass optical window (5) inner bottom is installed with semiconductor cooler (10), and described half The top of conductor refrigerator (10) is equipped with golden soldering tablet (1003), and is equipped with chip (9), institute on golden soldering tablet (1003) The top for stating substrate (1) is symmetrically equipped with two groups of second electrodes (7), and the bottom of the substrate (1) is symmetrically equipped with Two groups of first electrodes (6), the substrate (1) are equipped with for connecting first electrode (6) and second electrode (7) to realize point up and down The conductance through-hole (101) of conducting, and conductance through-hole (101) is set to the inside or edge of substrate (1), second described in one group One end is electrically connected at one end of chip (9) electrode, second electrode described in another group by binding gold thread (8) at the top of electrode (7) (7) top one end is electrically connected at one end of semiconductor cooler (10) electrode by binding gold thread (8).

2. a kind of SMD-UV-LED of vacuum tight encapsulation according to claim 1, it is characterised in that：The substrate (1) For aluminium nitride substrate, specification is SMD6060, is made of aluminium nitride ceramics material, and the thermal conductivity of aluminium nitride ceramics be 170~ 230W/mK。

3. a kind of SMD-UV-LED of vacuum tight encapsulation according to claim 1, it is characterised in that：The semiconductor causes Cooler (10) further includes TEC cold ends (1001) and the hot junctions TEC portion (1002), and the TEC cold ends (1001) are located at semiconductor The top of refrigerator (10), the hot junctions TEC portion (1002) are located at the bottom end of semiconductor cooler (10).

4. a kind of SMD-UV-LED of vacuum tight encapsulation according to claim 1, it is characterised in that：The chip (9) Can be the chips such as UV UV A-LED, UVB-LED, UVC-LED, FP, DFB, VCSEL, and chip (9) is sealed using miniaturized SMD Dress.

5. a kind of preparation method of the SMD-UV-LED of vacuum tight encapsulation described in claim 1, which is characterized in that including such as Lower step：

S1, substrate holder use aluminium nitride (ALN+TEC+ metallization) substrate holder, and specification is SMD6060, and cleaning, drying is spare；

S2, chip：Using the UV-LED chips of 60mW, 190~280 nanometers of wavelength, gold thread diameter 30um is spare；

S3, glass optical window use 60*60 mm of thickness for 0.3 millimeter of quartz glass square piece, and bottom is using metallization and fusion The solder of gold-tin alloy.Solder region is that quartz square chip surrounding width is 0.5 millimeter, the golden tin that thickness is 10 microns Alloy frame；

S4, aluminium nitride substrate laser boring：It is punched in advance according to circuit design, i.e. conductance through-hole；

S5, chip are welded by 300 degree of eutectics and the bonding of TEC cold ends, is connected with two electrodes of substrate holder by gold thread.TEC is supplied Electrode is also connected with gold thread with other two electrode in substrate holder, completes chip fixation and wiring process；

S6, the material for completing S5 links is placed on graphite fixture, chip upward, by 60*60 millimeters of quartz glass optical window, Being placed on one side on the ceramic base panel seat of surface metalation with solder, is positioned by graphite fixture, be placed on nitrogen (or Argon gas) protection soldering and sealing stove in；

S7, technical indicator test:UV UV-LED prepared by the present invention carry out and the product of currently employed organic glue bond with And carry out contrast test without the air-tight packaging product correlated performance and reliability of TEC structures.

6. the preparation method of the SMD-UV-LED of vacuum tight encapsulation according to claim 5 a kind of, it is characterised in that：Institute The temperature set interval for stating the soldering and sealing furnace interior in S6 is respectively 100~120 DEG C；200~250 DEG C；280~300 DEG C；150~ 200℃；30~50 DEG C of one of which is multigroup.