CN105702815A - Manufacturing method for flip LED chip - Google Patents

Abstract

The invention discloses a manufacturing method for a flip LED chip. A funnel-shaped protection layer is arranged around an ITO layer, a reflective layer and a barrier layer based on different etching selection ratios and a creative deposition manner, wherein the funnel-shaped opening of the protection layer has a bigger upper part and a smaller lower part. The problem of frequent electric leakage of the existing flip LED chip is solved.

Description

Manufacturing method of flip-chip LED chip

technical field

The invention belongs to the field of photoelectric technology, and in particular relates to a manufacturing method of a flip-chip LED chip.

Background technique

Light-emitting diode (LED) has significant advantages such as long life, energy saving and environmental protection. It is considered to be another revolution in lighting technology after incandescent lamps and fluorescent lamps. It is currently the focus of research and development and industry attention in the field of semiconductors and lighting in the world. prospect. In order to solve the problem of electrode shading and improve brightness, flip-chip LED chip technology has more and more research and development value and market prospects.

As shown in Figure 1, the flip-chip design involves a structure in which a protective layer wraps the reflective silver mirror. However, due to evaporation, yellow light defects, etc., there will be abnormalities such as silver migration and leakage.

Contents of the invention

The object of the present invention is to provide a method for manufacturing a flip-chip LED chip, which solves the problem that the conventional flip-chip LED chip is prone to electric leakage due to silver migration.

According to the present invention, a method for manufacturing a flip-chip LED chip is provided, comprising steps:

S1. Provide a light-emitting epitaxial layer, and grow an ITO layer on the light-emitting epitaxial layer;

S2, patterning the light-emitting epitaxial layer and the ITO layer;

S3, depositing a protective layer, the protective layer covering the ITO layer;

S4, making a pattern protective layer, and making pits penetrating to the ITO layer on the pattern protective layer, the protective layer after making is funnel-shaped, and the funnel-shaped opening is large and small at the bottom;

S5. Deposit a reflective layer in the pit, partially or completely deposit the reflective layer in the pit, and cover the barrier layer on the reflective layer.

Further, in step 4, pits are formed on the protective layer by photomask etching.

Further, in step 4, the photomask is etched through the photoresist, and the etching selectivity of the photoresist to the protective layer is smaller than that of the photoresist to the ITO layer.

Further, in step 5, the reflective layer is grown by small-angle deposition, and the barrier layer is grown by large-angle deposition.

Further, in step 3, a protective layer is formed by depositing a material with reflective and inert properties.

Further, in step 3, a protective layer is formed by depositing one or any combination of Ti, TiW, and DBR materials.

Further, the growth thickness d _i of the ITO layer in step 1 is 0.06 μm to 0.2 μm, which is thicker than the conventional ITO layer, which is convenient for making pits in the ITO layer in step 4, and enlarging the protective effect of wrapping the reflective layer.

Compared with the prior art, the manufacturing method of the flip-chip LED chip of the present invention at least includes the following technical effects:

(1) Form a funnel-shaped protective layer through the difference in etching ratio between the photoresist and the protective layer and the ITO layer;

(2) Through the small-angle production deposition of the reflective layer and the large-angle growth of the deposition barrier layer, the process flow of the flip-chip LED chip is efficiently completed, and at the same time, the protective layer does not completely cover the reflection caused by the warping of the metal edge after the traditional metal lift-off process Migration of reflective layer material caused by problems such as layer or residual photoresist. .

(3) Compared with the conventional process, thickening and growing the ITO layer reduces the difficulty of making the pit-wrapped reflective layer, while avoiding damage to the light-emitting epitaxial layer.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the features particularly pointed out in the written description, claims hereof as well as the appended drawings.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In addition, the drawing data are descriptive summaries and are not drawn to scale.

Figure 1: A cross-sectional schematic diagram of an existing flip-chip LED chip structure;

Fig. 2: the sectional schematic diagram that embodiment is made to step 1;

Fig. 3: the sectional schematic diagram that embodiment is made to step 2;

Fig. 4: the sectional schematic diagram that embodiment is made to step 3;

Fig. 5 ~ Fig. 6: the cross-sectional schematic diagram of embodiment making step 4;

Fig. 7: the sectional schematic diagram that embodiment is made to step 5;

The symbols in the figure indicate: 1: light-emitting epitaxial layer, 2: reflective layer, 3: barrier layer, 4: ITO layer, 5: protective layer.

detailed description

For a thorough understanding of the present invention, detailed steps and components thereof will be presented in the following description. In addition, well-known components or steps are not described in detail to avoid unnecessary limitations of the present invention. The preferred embodiments of the present invention will be described in detail as follows. However, in addition to these detailed descriptions, the present invention can also be widely implemented in other embodiments, and the scope of the present invention is not limited, and the scope of patent rights shall prevail.

The present invention proposes a process suitable for flip-chip LED chips, which improves the conventional problem that flip-chip LED chips are prone to electric leakage.

Example

This embodiment provides a method for manufacturing a flip-chip LED chip, including steps:

S1. Referring to FIG. 2, a light emitting epitaxial layer 1 is provided, and an ITO layer 4 is grown on the light emitting epitaxial layer 1;

S2. Referring to FIG. 3 , making a core pattern light-emitting epitaxial layer 1 and making a patterned ITO layer 4;

S3, with reference to Fig. 4, deposit protection layer 1, cover ITO layer 4, protection layer 5 is made up of inert material, preferably has the inert material of reflective property, and this embodiment is preferably Ti, also can be materials such as TiW, DBR or any combination. While improving the material migration of the reflective layer, increase the backlight;

S4, with reference to Fig. 5 and Fig. 6, make graphic protective layer, and make the pit that runs through to ITO layer 4 on graphic protective layer, the protective layer after making is funnel-shaped, and the opening of described funnel-shaped is big on the bottom and small;

S5 , referring to FIG. 7 , depositing a reflective layer 2 in the pit, partially or completely depositing the reflective layer 2 in the pit, and covering the barrier layer 3 on the reflective layer 2 .

Specifically, compared with the conventional process in step 1, a thicker ITO layer 4 is grown in this embodiment to facilitate the formation of pits penetrating to the ITO layer 4 in step 4. The thickness d _i of the ITO layer 4 is 0.06 μm to 0.2 μm, Compared with the conventional process, thickening and growing the ITO layer 4 reduces the difficulty of making the pit-wrapping reflective layer 2 in step 4, and at the same time avoids etching damage to the light-emitting epitaxial layer 1 . Part of the upper surface of the ITO layer 4 is in contact with the protective layer 5 , and part or all of the reflective layer 2 is located in the pit. A structure in which the barrier layer 3 and the ITO layer 4 are wrapped around the reflective layer 2 is formed to prevent material migration of the reflective layer 2 . .

Step 4 uses photoresist to carry out photomask etching, utilizes BCl ₃ , SiCl ₄ or Cl ₂ gas to carry out dry etching to make pits on protective layer 5, and the etching selectivity ratio of described photoresist to protective layer 5 is smaller than photoresist to photoresist to The etching selectivity of the ITO layer 4 means that the photoresist etches the protective layer 5 more slowly than the etching of the ITO layer 4 . Preferably, the etching selectivity ratio of the photoresist to the protection layer 5 is 0.3-0.8, and the etching selectivity ratio to the ITO layer 4 is 1-1.4. According to the difference in etching selectivity, the protective layer 5 is funnel-shaped after etching, with a large opening and a small opening. The inner side of the protective layer 5 has at least one slope surface, and the slope angle α of the slope surface is 30°~75°. Layer 4, reflective layer 2 and barrier layer 3 are wrapped inside, and due to the funnel-shaped structure, the contact area between barrier layer 3 and protective layer 5 is increased, and under the influence of funnel _- shaped structure, the area Su of the upper surface of barrier layer 3 is larger than that The area S _d of the surface provides a better sealing effect for the material of the reflective layer 2 and improves stability and reliability.

The material of the barrier layer 3 can be selected from one of Ti, TiW, Ni, Pt or any combination, the thickness d _b of the barrier layer 3 is twice or more than the thickness d _r of the reflective layer 2, and the thickness d _p of the protective layer 5 is the reflective layer 2 Thickness d _r 4 times or more.

Step 5. Deposit the reflective layer 2 in the pit at a small angle using evaporation equipment such as E-Gun to prevent the reflective layer 2 from covering the barrier layer 3 at a large angle on the reflective layer 2 with Sputter sputtering equipment, so that it can be produced quickly by evaporation and sputtering The reflective layer 2 and the barrier layer 3, in addition to shortening the production cycle, saving production resources, and reducing production costs, can also solve the problem that the protective layer 5 does not completely cover the reflective layer 2 due to the warping of the edge of the metal layer after the traditional metal stripping process. Or incomplete cleaning leads to the migration of the material of the reflective layer 2 caused by problems such as residual photoresist.

In step 5, the material of the reflective layer 2 is preferably Ag or Al, and the protective layer 5 prevents the material of the reflective layer 2 from migrating.

It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention is described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand; The technical solutions described in the examples are modified, or some or all of the technical features are equivalently replaced, and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the embodiments of the present invention.

Claims (7)

1. the manufacture method of flip LED chips, including step:

S1, provide a light emitting epitaxial layer, light emitting epitaxial layer grows ITO layer；

S2, by graphical to light emitting epitaxial layer, ITO layer；

S3, deposition protective layer, described protective layer covers ITO layer；

S4, making graphic protection, and on graphic protection, make the pit being through to described ITO layer, the protective layer after making is funnel-form, and described funnelform opening is up big and down small；

S5, in described pit deposition of reflective layer, described reflecting layer is some or all of to be deposited in pit, covering barrier layer on described reflecting layer；

The effect of described protective layer is in that to stop the material transition in reflecting layer。

2. the manufacture method of flip LED chips according to claim 1, it is characterised in that: step 4 is etched by light shield and makes pit on the protection layer。

3. the manufacture method of flip LED chips according to claim 2, it is characterised in that: step 4 makes to carry out with photoresist light shield etching, described photoresist to the etching selectivity of protective layer less than the described photoresist etching selectivity to ITO layer。

4. the manufacture method of flip LED chips according to claim 1, it is characterised in that: step 5 is by reflecting layer described in low-angle deposition growing, by barrier layer described in wide-angle deposition growing。

5. the manufacture method of flip LED chips according to claim 1, it is characterised in that: step 3 forms protective layer by depositing the material possessing reflection and inert nature。

6. the manufacture method of flip LED chips according to claim 5, it is characterised in that: step 3 passes through the one in the material of depositing Ti, TiW, DBR or combination in any, formation of deposits protective layer。

7. the manufacture method of flip LED chips according to claim 1, it is characterised in that: the ITO layer growth thickness d in step 1_iIt it is 0.06 μm to 0.2 μm。