CN207116465U

CN207116465U - A kind of easily encapsulation easy heat radiation upside-down mounting high voltage LED chip

Info

Publication number: CN207116465U
Application number: CN201720317494.5U
Authority: CN
Inventors: 熊德平; 何苗; 赵韦人; 陈丽; 冯祖勇; 雷亮
Original assignee: Guangdong University of Technology
Current assignee: Guangdong University of Technology
Priority date: 2017-03-29
Filing date: 2017-03-29
Publication date: 2018-03-16
Anticipated expiration: 2027-03-29

Abstract

The utility model proposes a kind of easily encapsulation, the upside-down mounting high voltage LED chip of easy heat radiation, include Sapphire Substrate, epitaxial layer, p and n-electrode, package substrate, when carrying out flip-chip packaged to this fabric chip, the alignment difficulty problem that chip electrode can be avoided too small with substrate circuit solder joint caused by overstocked, encapsulation is set to be easier to realize；In addition, each sub- chip all makes long narrow bar shaped, not only improve being uniformly distributed for electric current, be advantageous to the radiating of each sub- chip again, there is insulating barrier cladding outside the p-electrode of each sub- chip, at flip-chip packaged each sub- chip can contact with substrates into intimate, avoid the formation of the air gap, make the radiating of whole chip faster.When making chip, the external insulation layer of metallic film is etched, it is only necessary to the p-electrode of the first sub- chip and the n-electrode part of the sub- chips of N are exposed, it is simpler that these make it that high-voltage chip makes.

Description

A kind of easily encapsulation easy heat radiation upside-down mounting high voltage LED chip

Technical field

The present invention relates to a kind of easily encapsulation easy heat radiation upside-down mounting high voltage LED chip structure, belong to semi-conductor LED chips manufacture neck Domain.

Background technology

Semiconductor lighting light emitting diode (LED) has light efficiency height, long lifespan, green, the saving energy etc. many excellent Point, the revolutionary technology in 21 century in new solid light source epoch is described as, is referred to as forth generation green light source.

As LED in the deep development of lighting field, traditional low-voltage LED increasingly exposes the drawbacks of intrinsic, including Driving power short life, conversion efficiency are low, and low-voltage LED thermal diffusivity is bad, it is impossible to worked under high current etc.；It is above-mentioned to solve Problem, in recent years formal dress high voltage LED chip arise, this high voltage LED chip is integrated multiple series connection on the same chip Sub- chip, this little chip is directly just completed in chip manufacturing proces, and it is excellent to have that light efficiency is high, power requirement is low etc. Point.Illuminating product to be developed using high-voltage LED, driving power can be greatly simplified, overall power consumption can also be greatly lowered, from And the design requirement of heat-dissipating casing is greatly lowered, also imply that the cost-effective reduction of illuminator.

Upside-down mounting high voltage LED chip has the incomparable advantage of positive cartridge chip again, and this chip is by light from substrate sapphire Emit, encapsulation process utilizes eutectic welding method, and the electrode of chip front side is aligned with the metal salient point on electrode of substrate Weld.In this inverted structure encapsulation process, it is not necessary to carry out electrode connection with gold thread, add the stability of encapsulation, n Type or the metal film layer on p-type GaN surfaces can both play conductive and current expansion, can play the work of reflection photon again With avoiding light directive substrate that LED is sent and absorbed, in addition, heat caused by the LED luminescent layers of inverted structure is directly transmitted to Substrate, there is more preferable radiating effect.

The content of the invention

It is an object of the invention to provide a kind of upside-down mounting high voltage LED chip structure of easily encapsulation easy heat radiation, formed highly reliable Interconnecting electrode, solve upside-down mounting high voltage LED chip electrode and the problems such as difficult, radiating is difficult be directed at during flip-chip packaged, and have There is the advantages that light extraction efficiency is high, and driving power is simple, have broad application prospects.

To achieve these goals, the present invention adopts the following technical scheme that：A kind of easily encapsulation easy heat radiation upside-down mounting high-voltage LED core Piece, including Sapphire Substrate, epitaxial layer, p-electrode and n-electrode, package substrate, the epitaxial layer are followed successively by n-type GaN, SQW Layer, p-type GaN layer, wherein, high-voltage chip is divided into each sub- chip by the epitaxial layer in Sapphire Substrate provided with deep isolation channel, Each sub- chips in etching goes out n-type GaN table tops, and the n-type table top and p-type table top of adjacent sub- chip are sequentially connected using reflective metal film Get up, insulating thin layer, the sub- chip n-type GaN of first sub- chip the p-type GaN and N are externally provided with the reflective metal film On metal film layer etching be exposed, form the p and n-electrode of high-voltage chip.

Preferably, each sub- chip that deep isolated groove is formed is strip, and the first sub- core of sub- chip and N Piece has the table top bigger than other sub- chips, and sub- chip chamber is connected with reflective metal film layer；

Preferably, the p, n-electrode and reflective metal film layer use the electric conductivity such as Ag, Ni, Al and reflecting properties all Preferable metal, single-layer metal structure can be used, multi-layer metal structure can also be used；

Preferably, described upside-down mounting high voltage LED chip conductive metal film inner insulating layer is using light transmission good SiO₂Film, external insulation layer is using the good Si of thermal conductivity₃N₄Film；

Preferably, the substrate uses AlN ceramic, substrate upper electrode metal salient point uses Au-Sn alloys.

Brief description of the drawings

Fig. 1 is easily encapsulation easy heat radiation upside-down mounting high-voltage LED structural representation of the present invention；

Fig. 2 is the planar structure schematic diagram of upside-down mounting high-voltage LED of the present invention；

Fig. 3 is the preparation method flow chart that easy heat radiation upside-down mounting high voltage LED chip is easily encapsulated in one embodiment of the invention；

Fig. 4-8 is each step structural representation of upside-down mounting high-voltage LED manufacturing process of the present invention.

Embodiment

In order that those skilled in the art more fully understand the present invention program, the present invention is made below according to accompanying drawing more detailed Thin explanation.All features, method or step disclosed in this specification, in addition to mutually exclusive feature or step, Combine in any way.Any feature disclosed in this specification, unless specifically stated otherwise, it can be replaced by other equivalent features Change, each feature be equivalent or similar characteristics in an example, unless there are special narration.

As shown in figure 1, a kind of easily encapsulation easy heat radiation upside-down mounting high voltage LED chip structure, including：Substrate 10, Sapphire Substrate 1st, n-type GaN layer 2, quantum well layer 3 and p-type GaN layer 4, external insulation film layer 5 and 6, p-electrode 7a and n-electrode 7b, deep isolating trenches Groove 11, conductive metal film layer 12, metal salient point 8, metal solder joints 9 on substrate.The deep isolated groove 11 is upside-down mounting high pressure core Piece epitaxial layer is separated into two or more sub- chips, and every sub- chip has a p-electrode and n-electrode independent of each other, and described the The p-electrode of the n-electrode of one sub- chip and the second sub- chip, passed sequentially through to N-1 chips n-electrode and the sub- chip p-electrodes of N Conductive metal film layer 12 connects, and has the cladding of insulating thin layer 5 and 6 inside and outside conductive metal film, in the first sub- chip p On the sub- chip n-type GaN of type GaN and N inner insulating layer film, p, the n-electrode 7a and 7b of upside-down mounting high-voltage chip are formed.Its feature It is, not only bottle opener chip chamber circuit connects but also plays reflected light conductive metal film, and it covers the P electrode of whole sub- chip Table top；There is high thermal conductivity insulating layer cladding outside conductive metal film, when carrying out flip-chip packaged to this fabric chip, in substrate It is corresponding that p, the n-electrode of area is larger and spacing is larger solder joint 9 and metal salient point 8 and high-voltage chip can be formed on 10, can The alignment difficulty problem for avoiding chip electrode too small with circuit caused by overstocked, encapsulation is set to be easier to realize；In addition, each sub- chip is all Long narrow bar shaped is made, not only improves being uniformly distributed for electric current, is advantageous to the radiating of each sub- chip again, each sub- chip and substrate are direct It is pressed into contact with, is also beneficial to the radiating of each sub- chip.

Preferably, the p, n-electrode and reflective metal film layer are all preferable using the electric conductivity such as Ag, Al and reflecting properties Metal, single-layer metal structure can be used, multi-layer metal structure can also be used；

Preferably, the substrate uses AlN, Si or metal material, substrate upper electrode metal salient point is closed using Au-Sn Gold.

A kind of upside-down mounting high voltage LED chip, its preparation method such as Fig. 4-8, comprises the following steps：

Step S1, grown epitaxial layer, is followed successively by n-type GaN layer, quantum well layer, p-type GaN layer on a sapphire substrate；

Poly- S2 is walked, after epitaxial growth terminates, the quantity of the potentiometer operator chip born according to the high-voltage chip of design, And according to the size of isolated area between each sub- chip and sub- chip, determine the size of high-voltage chip and institute is right in epitaxial wafer The specific region answered；Photoetching process is recycled, the isolation channel that sub- chip chamber is carried out to this specific region of epi-layer surface etches, Until Sapphire Substrate is exposed, etching depth is 5-10 μm；Then the subregion of each sub- chip is etched again, revealed Go out n-type GaN layer and form table top, etching depth is 1-5 μm, and footprint to the greatest extent may be used when meeting the Ohmic contact requirement of n-type GaN layer Can be small；

Poly- S4 is walked, after the completion of isolation channel and n-type table top, using plasma enhanced chemical vapor deposition (PECVD) skill Art, one layer of SiO is covered on the whole face of high-voltage chip₂Insulating thin layer, SiO₂Thickness 300nm-500nm, then recycle photoetching skill Art carries out the etching of electrode through hole, in SiO₂The n-electrode and p-electrode through hole of each sub- chip are formed on insulating thin layer respectively；

Step S5, the Ni with high reflectance is then plated in the whole face of chip using magnetic control sputtering device or thermal evaporation apparatus (5nm)/Ag (200nm) metal film layer, then the mesa side walls metal film layer of every sub- chip p-electrode is etched away, ensure same The n-electrode and p-electrode of one sub- chip form circuit and disconnected；

Step S6, the Si with high-termal conductivity is then covered using PECVD again in whole chip₃N₄Insulating thin layer, Si₃N₄Thickness 300nm-500nm, then photoetching is carried out to this insulating thin layer, on the p-type GaN of the first sub- chip and the sub- cores of N The p-electrode and n-electrode of high-voltage chip are formed on the n-type GaN of piece respectively；

Poly- S7 is walked, using the AlN ceramic by directly covering copper method (DBC) metallization, as face-down bonding high-voltage LED The baseplate material of chip, Au-Sn alloy bumps are prepared thereon using galvanoplastic；Using hot pressing ultra-sonic welding techniques, upside-down mounting P-electrode and the n-electrode metal salient point corresponding with substrate of high voltage LED chip weld, and to ensure each sub- chip with Substrates into intimate contacts, and avoids the formation of air-gap；Finally, it is roughened in sapphire substrate surface, with improving extraction efficiency.

In the case where not departing from spiritual or necessary characteristic of the invention, the present invention can be embodied in other specific forms.Should The specific embodiment each side is considered merely as illustrative and non-limiting.Therefore, scope of the invention such as appended claims It is shown in scope rather than shown as indicated above.It is all fall change in the equivalent meaning and scope of claim should be regarded as Fall in the category of claim.

Claims

A kind of 1. upside-down mounting high voltage LED chip, it is characterised in that including：Sapphire Substrate, epitaxial layer, p and n-electrode, isolated groove, External insulation film layer, conductive metal film layer, package substrate, the epitaxial layer include n-type GaN layer, quantum well layer and p successively Type GaN layer；Upside-down mounting high-voltage chip epitaxial layer is separated into two or more sub- chips, every sub- chip by the isolated groove There is the p-electrode of p-electrode and n-electrode independent of each other, the n-electrode of the first sub- chip and the second sub- chip, to N-1 chips n Electrode and the sub- chip p-electrodes of N pass sequentially through conductive metal film layer and connected, and have insulating barrier inside and outside conductive metal film Film coated, on the first sub- chip n-type GaN of sub- chip p-type GaN and N inner insulating layer film, form upside-down mounting high-voltage chip P and n-electrode.
2. upside-down mounting high voltage LED chip according to claim 1, it is characterised in that good using Ag, Ni or Al reflecting properties Metal is as conductive metal film layer, and metallic conduction film layer covers each sub- chip p-type GaN table tops on each sub- chip p-type GaN.
3. upside-down mounting high voltage LED chip according to claim 1, it is characterised in that the interior insulation of the conductive metal film layer Layer is using the good SiO of translucency₂, external insulation layer is using the good Si of heat dispersion₃N₄Film.
4. upside-down mounting high voltage LED chip according to claim 1, it is characterised in that each sub- chip uses string configuration, First, which compares other sub- chips with the sub- chips of N, has bigger table top.