CN104701435A - Light emitting element and manufacturing method thereof - Google Patents

Abstract

The invention discloses a light-emitting element and a manufacturing method thereof. The disclosed light-emitting element includes: a metal connection structure; the barrier layer is positioned on the metal connecting structure and comprises a first multi-layer metal layer positioned on the metal connecting structure and a second multi-layer metal layer positioned on the first multi-layer metal layer; the metal reflecting layer is positioned on the barrier layer; and the light-emitting laminated layer is electrically connected with the metal reflecting layer; the first multi-layer metal layer comprises a first metal layer made of a first metal material and a second metal layer made of a second metal material, the first metal layer is closer to the metal connecting structure than the second metal layer, the second multi-layer metal layer comprises a third metal layer made of a third metal material and a fourth metal layer made of a fourth metal material, the third metal layer is closer to the second metal layer than the fourth metal layer, the first metal material is different from the second metal material, and the third metal material is different from the fourth metal material.

Description

Light emitting element and manufacturing method thereof

technical field

The invention relates to a light-emitting element and a manufacturing method thereof; in particular, to a light-emitting element with holes and a manufacturing method thereof.

Background technique

Figure 1 shows a conventional light emitting diode structure, including a permanent substrate 109, above which there is a light emitting stack 102, a metal reflective layer 106, a barrier layer 107, and a metal connection Structure 108. In addition, a first electrode 110E1 and its extension electrode 110E1' are disposed on the light emitting stack 102, and a second electrode 110E2 is disposed on the permanent substrate 109 for transmitting current.

The metal reflective layer 106 is used to reflect the light emitted by the light-emitting stack 102 , and the metal connection structure 108 is formed by bonding two layers of materials to form an alloy so that the permanent substrate 109 and the barrier layer 107 are bonded. The barrier layer 107 is located between the metal reflective layer 106 and the metal connection structure 108 to prevent metal diffusion between the metal reflective layer 106 and the metal connection structure 108 . However, the metal connecting structure 108 is generally bonded at high temperature, that is, the bonding temperature is higher than 300° C., so the material composition of the metal connecting structure 108 is usually different from that of the metal reflective layer 106, that is, the material composition of the metal connecting structure 108 is different from that of the metal reflective layer 106. Layers 106 do not have the same metal element. For example, the existing metal reflective layer 106 adopts silver (Ag); and the metal connection structure 108 adopts an alloy mainly containing zinc (Zn), such as an alloy of zinc (Zn) and aluminum (Al), to facilitate high-temperature bonding. When the material of the metal reflective layer 106 and the metal connection structure 108 do not have the same metal element, the design of the existing barrier layer 107 adopts the design of a thin barrier layer (less than 100nm) to prevent the metal reflective layer 106 from contacting the metal. The effect of metal diffusion between the connecting structures 108 .

However, with the development of light-emitting diode applications, the performance requirements are gradually increasing. For example, when light-emitting diodes are used in the automotive field, because cars are closely related to personal safety, the reliability requirements for automotive light-emitting diodes are also higher than general applications such as The display is high, so it is necessary to use a reflector material with better stability. Compared with silver metal, which may cause silver metal migration, making the metal reflective layer 106 with other metal materials has its advantages. In addition, as the metal connection structure 108 develops towards low-temperature bonding, the material of the metal connection structure 108 also requires more selection changes. Therefore, when the material of the metal reflective layer 106 and the metal connection structure 108 are selected to have the same metal element, because the two sides of the barrier layer 107 have the same metal element, other elements in the alloy of the metal connection structure 108 are in the barrier layer. The two sides of 107 are particularly easy to combine, so the design of the thin barrier layer will not be able to effectively prevent the metal diffusion between the metal reflective layer 106 and the metal connecting structure 108. The metal in the alloy of the metal connection structure 108 diffuses into the metal reflective layer 106 , which reduces the reflectivity of the metal reflective layer 106 and reduces the brightness of the LED.

Contents of the invention

The object of the present invention is to provide a light-emitting element and a manufacturing method thereof, so as to solve the above-mentioned problems.

To achieve the above purpose, the light-emitting element disclosed in the present invention includes: a metal connection structure; a barrier layer located on the above metal connection structure, including a first multi-layer metal layer located on the above metal connection structure and a second A multi-layer metal layer is located on the above-mentioned first multi-layer metal layer; a metal reflective layer is located on the above-mentioned barrier layer; and a light-emitting laminate is electrically connected to the above-mentioned metal reflective layer; wherein the above-mentioned first multi-layer metal layer is composed of a A first metal layer made of a first metal material and a second metal layer made of a second metal material, the first metal layer is closer to the metal connection structure than the second metal layer, and the second multilayer metal The layers include a third metal layer made of a third metal material and a fourth metal layer made of a fourth metal material, the third metal layer being closer to the second metal layer than the fourth metal layer, and the The first metal material is different from the second metal material, and the third metal material is different from the fourth metal material.

The present invention also discloses a light-emitting element comprising: a metal connection structure; a barrier layer located on the metal connection structure, including a first multi-layer metal layer located on the metal connection structure and a second multi-layer metal layer Located on the above-mentioned first multi-layer metal layer; a metal reflective layer is located on the above-mentioned barrier layer; and a light emitting stack is electrically connected to the above-mentioned metal reflective layer; wherein the above-mentioned metal connection structure and the above-mentioned metal reflective layer include a same metal element, and the barrier layer includes a metal element different from the metal reflective layer.

Description of drawings

Fig. 1 is an existing light-emitting diode structure;

2A to 2I are the light-emitting element and its manufacturing method according to the first embodiment of the present invention;

3A and 3B are used to illustrate the barrier layer in the first embodiment.

Symbol Description

102 Luminous Laminations

106 metal reflective layer

107 barrier layer

108 metal connection structure

109 permanent substrate

110E1 first electrode

110E1’ Extended electrode

110E2 Second electrode

201 growth substrate

202 Luminous Lamination

202a first electrical semiconductor layer

202b luminescent layer

202c Second electrical semiconductor layer

203 dielectric layer

2031 piercing

204 The first transparent conductive oxide layer

205 Second transparent conductive oxide layer

206 metal reflective layer

207 barrier layer

2071a, 2071a' first metal layer

2071b second metal layer

2072a third metal layer

2072b fourth metal layer

207i anti-oxidation layer

208 metal connection structure

2081 First bonding layer

2082 Second bonding layer

2083 third bonding layer

209 permanent substrate

210E1 first electrode

210E1’ Extended electrode

210E2 Second Electrode

211 protective layer

212r Coarsening structure

Detailed ways

2A-FIG. 2I are the light-emitting element and its manufacturing method according to the first embodiment of the present invention. As shown in FIG. The semiconductor stack includes a first electrical type semiconductor layer 202a from bottom to top; a light emitting layer 202b located on the first electrical type semiconductor layer 202a; and a second electrical type semiconductor layer 202c located on the light emitting layer 202b . The first electrical type semiconductor layer 202a and the second electrical type semiconductor layer 202c are electrically different, for example, the first electrical type semiconductor layer 202a is an n-type semiconductor layer, while the second electrical type semiconductor layer 202c is a p-type semiconductor layer. The first electrical type semiconductor layer 202a, the light emitting layer 202b, and the second electrical type semiconductor layer 202c are formed of III-V group materials, such as aluminum gallium indium phosphide (AlGaInP) series materials.

Next, as shown in FIG. 2B , a dielectric layer 203 is formed on the light emitting stack 202 , and the dielectric layer 203 has a refractive index lower than that of the light emitting stack 202 . The material of the dielectric layer 203 includes, for example, a material selected from the group consisting of silicon oxide (SiO _x ), magnesium fluoride (MgF ₂ ), and silicon nitride (SiN _x ), and the thickness of the dielectric layer 203 is about 50 nm. The thickness of the dielectric layer 203 in this embodiment is 100 nm. Next, as shown in FIG. 2C, a plurality of through-holes 2031 are formed in the dielectric layer 203 to penetrate the dielectric layer 203 by photolithography and etching processes. The through-holes 2031 are approximately circular (not shown) from the top It has a diameter D, and the diameter D is approximately between 5 μm and 15 μm. In this embodiment, the diameter D is approximately 10 μm.

Next, as shown in FIG. 2D, a first transparent conductive oxide layer 204 is formed on the dielectric layer 203 and filled into the through hole 2031, so that the first transparent conductive oxide layer 204 forms an ohmic contact with the light emitting stack 202, the first The thickness of the transparent conductive oxide layer 204 is about to Between, the thickness of the first transparent conductive oxide layer 204 in this embodiment is Then, a second transparent conductive oxide layer 205 is formed on the first transparent conductive oxide layer 204, wherein the second transparent conductive oxide layer 205 is mainly used to provide the function of lateral (perpendicular to the stacking direction of each layer) current diffusion, Its material is different from that of the first transparent conductive oxide layer 204 . The thickness of the second transparent conductive oxide layer 205 is about 0.5 μm to 3 μm, and the thickness of the second transparent conductive oxide layer 205 in this embodiment is 1.0 μm. It should be noted that the thickness of the second transparent conductive oxide layer 205 is significantly thicker than the thickness of the first transparent conductive oxide layer 204 and the dielectric layer 203, so as shown in the figure, after the second transparent conductive oxide layer 205 is formed , the perforation 2031 can be filled up, and the uneven height difference caused by the perforation 2031 can be returned to a relatively flat surface. The first transparent conductive oxide layer 204 and the second transparent conductive oxide layer 205 comprise a material selected from the group consisting of indium tin oxide (Indium Tin Oxide, ITO), aluminum zinc oxide (Aluminum Zinc Oxide, AZO), cadmium tin oxide, antimony tin oxide, A group consisting of zinc oxide (ZnO), zinc tin oxide, and indium zinc oxide (Indium Zinc Oxide, IZO). In this embodiment, the material of the first transparent conductive oxide layer 204 is Indium Tin Oxide (ITO), and the material of the second transparent conductive oxide layer 205 is Indium Zinc Oxide (IZO).

Next, as shown in FIG. 2E , a metal reflective layer 206 is formed on the second transparent conductive oxide layer 205 , and the metal reflective layer 206 includes a metal material for reflecting the light emitted by the light emitting stack 202 . In this embodiment, the metal reflective layer 206 may have a reflectivity greater than 90% for the light emitted by the light emitting stack, such as gold (Au).

Next, as shown in FIG. 2F, a barrier layer 207 is formed on the metal reflective layer 206. The barrier layer 207 is used to prevent metal diffusion between the metal reflective layer 206 and the metal connection structure 208 (to be described later). . An embodiment of the barrier layer 207 is shown in FIG. 3A or FIG. 3B , which will be described in detail later. Next, a first bonding layer 2081 is formed on the barrier layer 207 , and a second bonding layer 2082 is formed on the first bonding layer 2081 . Next, as shown in FIG. 2G , a permanent substrate 209 is provided, and a third bonding layer 2083 is formed on the permanent substrate 209, and the third bonding layer 2083 is bonded to the second bonding layer 2082, and after bonding, the The growth substrate 201 is removed, as shown in FIG. 2H . The first bonding layer 2081 , the second bonding layer 2082 , and the third bonding layer 2083 form a metal connection structure 208 . The metal connection structure 208 includes a low-temperature fusion material with a melting point less than or equal to 300° C. The low-temperature fusion material includes indium (In) or tin (Sn), for example. In this embodiment, the low-temperature fusion material contains indium (In). For example, when the material of the first bonding layer 2081 is gold (Au), the second bonding layer 2082 When the material of the third bonding layer 2083 is indium (In) and the material of the third bonding layer 2083 is gold (Au), the first bonding layer 2081, the second bonding layer 2082, and the third bonding layer 2083 can be made at a low temperature, for example, the temperature is less than At or equal to 300° C., due to the eutectic effect, an alloy is formed and bonded to form a metal connection structure 208 , and the metal connection structure 208 includes an alloy of indium (In) and gold (Au). In another embodiment, the second bonding layer 2082 may be formed on the first bonding layer 2081 and bonded with the third bonding layer 2083 on the permanent substrate 209 to form the metal connection structure 208 .

Next, as shown in FIG. 2I , the first electrode 210E1 and its extension electrode 210E1' are formed on the light emitting stack 202 . Then, a part of the periphery of the light-emitting stack 202 is removed and part of the dielectric layer 203 is exposed through a photolithography and etching process, and a process of roughening the surface of the light-emitting stack 202 can be selectively implemented, so that in the second A roughened structure 212r is formed on the electrical semiconductor layer 202a, and then a protection layer 211 is formed on the light emitting stack 202 and the exposed dielectric layer 203, the protection layer 211 not covering the first electrode 210E1 and its extension electrode 210E1'. Finally, the second electrode 210E2 is formed on the permanent substrate 209 .

FIG. 3A is used to illustrate the barrier layer 207 in the above embodiment. FIG. 3A illustrates the barrier layer 207 in FIG. 2I , please refer to FIG. 3A and FIG. 2I at the same time. As mentioned above, the barrier layer 207 is located between the metal reflective layer 206 and the metal connection structure 208 to prevent metal diffusion between the two. The barrier layer 207 of this embodiment includes a first multilayer metal layer 2071 located on the metal connection structure 208 and a second multilayer metal layer 2072 located on the first multilayer metal layer 2071; wherein the first multilayer metal layer The layer 2071 includes a first metal layer 2071a made of a first metal material and a second metal layer 2071b made of a second metal material, the first metal layer 2071a is closer to the metal connection structure 208 than the second metal layer 2071b; The second multilayer metal layer 2072 includes a third metal layer 2072a made of a third metal material and a fourth metal layer 2072b made of a fourth metal material, the third metal layer 2072a is larger than the fourth metal layer 2072b close to the second metal layer 2071b. In terms of material selection, the first metal material is different from the second metal material, the third metal material is different from the fourth metal material, and the material selection of the above metal materials makes the barrier layer 207 contain a metal different from the metal reflective layer 206. element. In this embodiment, the materials of the first metal layer 2071 a and the third metal layer 2072 a include platinum (Pt), and the materials of the second metal layer 2071 b and the fourth metal layer 2072 b include titanium (Ti). Platinum (Pt) in the first metal layer 2071a and the third metal layer 2072a is used as a material that mainly prevents metal diffusion between the metal reflective layer 206 and the metal connection structure 208, while the material of the second metal layer 2071b and the fourth metal layer 2072b adopts Titanium (Ti) can increase the adhesion (adhesion), especially the titanium (Ti) of the fourth metal layer 2072b is in contact with the metal reflective layer 206 to provide good adhesion between the overall barrier layer 207 and the metal reflective layer 206, That is to say, in terms of the selection and arrangement of materials, it is better to choose that the adhesion force between the material of the fourth metal layer 2072b and the metal reflection layer 206 is greater than the adhesion force between the third metal layer 2072a and the metal reflection layer 206, so as to strengthen the third metal layer 2072a and the adhesion between the metal reflective layer 206. In terms of thickness, the thickness of the first metal layer 2071a and the third metal layer 2072a is about to Between, the thickness of the second metal layer 2071b and the fourth metal layer 2072b is about to between. In this embodiment, the thicknesses of the first metal layer 2071a and the third metal layer 2072a are about to Between, the thickness of the second metal layer 2071b and the fourth metal layer 2072b is about to between. The structure of the first multilayer metal layer 2071 and the second multilayer metal layer 2072 formed by the above thickness range can effectively prevent metal diffusion between the metal reflective layer 206 and the metal connection structure 208, and will not cause stress due to excessive thickness, However, the above-mentioned bonding process between the bonding layers in the subsequent metal connection structure 208 is affected.

Therefore, with the final structure of FIG. 2I and referring to FIG. 3A, the light-emitting element of the first embodiment of the present invention includes at least one metal connection structure 208; a barrier layer 207 is located on the metal connection structure 208, including a first multiple A metal layer 2071 is located on the metal connection structure 208 and a second multi-layer metal layer 2072 is located on the first multi-layer metal layer 2071; a metal reflective layer 206 is located on the barrier layer 207; and a light emitting stack 203 Electrically connected to the metal reflective layer 206; wherein the first multilayer metal layer 2071 includes a first metal layer 2071a made of the first metal material platinum (Pt) and a second metal layer 2071b made of the second metal material titanium (Ti) , the first metal layer 2071a is closer to the metal connection structure 208 than the second metal layer 2071b, and the second multilayer metal layer 2072 includes a third metal layer 2072a made of a third metal material platinum (Pt) and a fourth metal material titanium (Ti) constitutes the fourth metal layer 2072b, and the third metal layer 2072a is closer to the second metal layer 2071b than the fourth metal layer 2072b. The first metal material is different from the second metal material, and the third metal material is different from the fourth metal material. In addition, as mentioned above, in this embodiment, the metal connecting structure 208 includes an alloy of indium (In) and gold (Au), and the metal reflective layer 206 includes gold (Au), so the metal connecting structure 208 and the metal reflective layer 206 contains an identical metallic element gold (Au). As described in the prior art, since both sides of the barrier layer 207 have the same metal element, other elements in the alloy of the metal connection structure 208 (indium (In) in this embodiment) are on both sides of the barrier layer 207. Both sides are easy to bond, so the design of the thin barrier layer in the prior art cannot effectively prevent the metal diffusion of indium (In) between the metal reflective layer 206 and the metal connection structure 208 . For the structure of FIG. 2I in the above-mentioned embodiment, if the barrier layer 207 is changed to a thin barrier layer structure, such as a single layer Platinum (Pt) is used as the barrier layer 207, and the elemental analysis is carried out by energy spectrum analyzer-line scanning (EDS linescan), and the content of indium (In) in the metal reflective layer 206 and the indium (In) in the metal connection structure 208 are measured. The content of In) is close, both are about 5 to 10 AU (Arbitrary Unit) (the average value is about 7.5 AU), which proves that the design of the thin barrier layer cannot effectively prevent indium (In) from being formed between the metal reflective layer 206 and the metal reflective layer 206. Metal diffusion between metal connection structures 208 . And when the barrier layer 207 adopts the structure of the above-mentioned FIG. 3A, since the barrier layer 207 of the above-mentioned FIG. 207 contains a metal element different from the metal reflective layer 206, so it can effectively prevent the metal diffusion of indium (In) between the metal reflective layer 206 and the metal connection structure 208, and compared with simply increasing the thickness in an attempt to improve the barrier layer to prevent In terms of the method of metal diffusion ability, the problem of stress caused by the thickening of the barrier layer can be avoided. Therefore, when the elemental analysis is also performed with the energy spectrum analyzer-line scanning, it can be measured that the content of indium (In) in the metal reflective layer 206 is significantly reduced, which is different from the content of indium (In) in the metal connection structure 208. The content of indium (In) in the metal reflective layer 206 is approximately the same as the content of indium (In) in the light-emitting laminated layer 202, both are less than about 5 AU (Arbitrary Unit), and the average value is only about 2 AU ( Arbitrary Unit). That is, the content of indium (In) in the metal reflective layer 206 (average value is about 2 AU) is less than half of its content in the metal connection structure 208 (average value is about 7.5 AU). . It is proved that the design of the barrier layer adopted in the embodiment of the present invention can effectively prevent the metal diffusion of indium (In) between the metal reflective layer 206 and the metal connection structure 208 .

It should be noted that the description of the barrier layer 207 in FIG. 3A is based on FIG. 2I, that is, the final structure of the light-emitting element. However, FIG. 2I is formed by turning the growth substrate 201 over and bonding it to the permanent substrate 209. In terms of the formation method, for example, according to FIG. 2F in the middle process, the fourth metal layer 2072b, the third metal layer 2072a, the second metal layer 2071b, and the first metal layer 2071a are sequentially formed on the metal reflective layer 206.

FIG. 3B is an embodiment of another barrier layer of the present invention. FIG. 3B is a modification of FIG. 3A , and FIG. 3B also illustrates the barrier layer 207 of FIG. 2I . Please refer to FIG. 3A and FIG. 2I at the same time. Likewise, the barrier layer 207 is located between the metal reflective layer 206 and the metal connection structure 208 to prevent metal diffusion between the two. The barrier layer 207 in this embodiment is substantially the same as the barrier layer 207 in FIG. The second multi-layer metal layer 2072 is located between the first multi-layer metal layer 2071 and an anti-oxidation layer 207i is added to prevent the second multi-layer metal layer 2072 from being oxidized during the manufacturing process. The material of the anti-oxidation layer 207i includes gold ( Au), with a thickness of approx. to between. The rest about the material or thickness etc. are the same as those in FIG. 3A above, and will not be repeated here. It should also be noted that in terms of formation methods, for example, as seen in Figure 2F in the middle process, the fourth metal layer 2072b, the third metal layer 2072a, the anti-oxidation layer 207i, the second metal layer 2071b, and the first metal layer A layer 2071a is sequentially formed on the metal reflective layer 206 . The anti-oxidation layer 207i can effectively prevent the second multilayer metal layer 2072 from being oxidized during the manufacturing process when the second multilayer metal layer 2072 and the first multilayer metal layer 2071 are not formed continuously in the same machine.

The above-mentioned embodiments are only illustrative to illustrate the principles and effects of the present invention, and are not intended to limit the present invention. Anyone with ordinary knowledge in the technical field of the present invention can modify and change the above-mentioned embodiments without violating the technical principle and spirit of the present invention. Therefore, the protection scope of the present invention is as listed in the above claims.

Claims (10)

1. a light-emitting component, comprises:

Metal connecting structure;

Barrier layer, is positioned on this metal connecting structure, comprises the first more metal layers, is positioned on this metal connecting structure, and the second more metal layers, is positioned on this first more metal layers;

Metallic reflector, is positioned on this barrier layer; And

Luminous lamination, is electrically connected this metallic reflector;

Wherein this first more metal layers comprises the first metal layer be made up of one first metal material and the second metal level be made up of one second metal material, this the first metal layer comparatively this second metal level close to this metal connecting structure, and this second more metal layers comprises the 3rd metal level be made up of one the 3rd metal material and the 4th metal level be made up of one the 4th metal material, 3rd metal level comparatively the 4th metal level close to this second metal level, and this first metal material is different with this second metal material, the 3rd metal material is different with the 4th metal material.

2. light-emitting component as claimed in claim 1, wherein this metal connecting structure comprises a fusing point, is less than or equal to the low temperature fusing material of 300 DEG C.

3. light-emitting component as claimed in claim 2, wherein this low temperature fusing material comprises indium (In).

4. light-emitting component as claimed in claim 1, wherein this metallic reflector comprises gold (Au).

5. light-emitting component as claimed in claim 1, wherein this metal connecting structure comprises the alloy of indium (In) and gold.

6. light-emitting component as claimed in claim 1, wherein this first metal material and the 3rd metal material comprise nickel (Ni) or platinum (Pt), and this second metal material and the 4th metal material comprise titanium (Ti).

7. light-emitting component as claimed in claim 1, also comprise dielectric layer, between this metallic reflector and this luminous lamination, this dielectric layer has a refractive index, is less than the refractive index of luminous lamination with this.

8. light-emitting component as claimed in claim 7, wherein this dielectric layer comprises a material and is selected from silica (SiO _x), magnesium fluoride (MgF ₂), and silicon nitride (SiN _x) group that forms.

9. light-emitting component as claimed in claim 3, wherein the content of this low temperature fusing material in this metallic reflector is roughly the same at the content of this luminous lamination with this low temperature fusing material, or the content of this low temperature fusing material in this metallic reflector is less than 1/2nd of the content of this low temperature fusing material in this metal connecting structure.

10. a light-emitting component, comprises:

Metal connecting structure;

Barrier layer, is positioned on this metal connecting structure, comprises the first more metal layers, is positioned on this metal connecting structure, and the second more metal layers, is positioned on this first more metal layers;

Metallic reflector, is positioned on this barrier layer; And

Luminous lamination, is electrically connected this metallic reflector;

Wherein this metal connecting structure and this metallic reflector comprise an identical metallic element, and this barrier layer comprises the metallic element different with this metallic reflector.