KR102061565B1 - The fabrication method of bonding metal and the fabrication method of semiconductor light emitting device using the same - Google Patents

Abstract

Forming first and second bonding metal layers on one surface of the first and second bonding objects, respectively, and forming the second bonding metal layer on the first bonding object so as to face the first bonding metal layer and the second bonding metal layer. It provides a method for forming a metal bonding layer comprising the step of placing the object, and the first and second bonding metal layer to form a eutectic metal bonding layer. At least one of the first junction metal layer and the second junction metal layer may have an antioxidant film formed on an upper surface thereof, and the antioxidant film may be formed of a metal or an alloy having a lower oxidation reactivity than the junction metal layer located below.

Description

Metal bonding layer forming method and manufacturing method of semiconductor light emitting device using same {THE FABRICATION METHOD OF BONDING METAL AND THE FABRICATION METHOD OF SEMICONDUCTOR LIGHT EMITTING DEVICE USING THE SAME}

The present invention relates to a metal bonding layer forming method and a semiconductor light emitting device manufacturing method using the same.

BACKGROUND ART A technique for bonding one object such as an electronic device to another object such as a substrate using a bonding metal has been widely used. In particular, in the case of manufacturing an electronic device such as a semiconductor light emitting device and transferring it to another substrate, a bonding technique using a eutectic metal is widely used to transfer to a permanent substrate.

However, undesired voids are generated in the eutectic metal bonding layer formed by the reaction between the bonding metals, thereby lowering the bonding strength. In particular, such a problem easily occurs when the surface is uneven to the surface to be joined, which is a large cause of the poor bonding between the objects.

In addition, even after the bonding object is bonded using the bonding metal, a problem may arise in which the bonding objects are separated from each other according to the surface state of the bonding metal.

Therefore, a method of forming a metal bonding layer in which connection strength and reliability are improved by suppressing elements that inhibit rigid bonding, such as voids generated during bonding between bonding objects, and a method of manufacturing a semiconductor light emitting device using the metal bonding layer is disclosed. It is required.

According to an aspect of the present invention, forming a first and a second bonding metal layer on one surface of a first and a second bonding object, respectively, and the first bonding so as to face the first bonding metal layer and the second bonding metal layer. Disposing the second bonding object on an object, and reacting the first and second bonding metal layers to form a eutectic metal bonding layer, wherein at least one of the first bonding metal layer and the second bonding metal layer is formed. Has an anti-oxidation film formed on its upper surface, and the anti-oxidation film provides a method of forming a metal bonding layer made of a metal or an alloy having a lower oxidation reactivity than the corresponding bonding metal layer located below.

At least one of the first and second bonding metal layers may include a metal or an alloy selected from the group consisting of Sn, In, Zn, Bi, Pb, Ni, Au, Pt, Cu, Co, and combinations thereof.

In this case, the anti-oxidation film is a material different from the material of the corresponding junction metal layer located below the metal, or an alloy selected from the group consisting of Pd, Pt, Ru, Rh, Ag, Os, Ir, Au, and combinations thereof. It may include. The antioxidant film may have a thickness of 10 kPa to 100 kPa.

At least one layer of the first and second bonding metal layers may further include a reaction delay layer made of a metal or an alloy to delay a reaction between the first and second bonding metal layers.

The reaction delay layer may include a metal or an alloy selected from the group consisting of Ti, W, Cr, Ta, and combinations thereof.

In a particular embodiment, at least one of the first and second bonding metal layers is formed on one surface of the first or second bonding object and comprises at least one metal of Ni, Pt, Au, Cu, and Co. From a group formed on a first reaction layer and on the first reaction layer, reacting with a metal of the first reaction layer to provide a eutectic metal, and consisting of Sn, In, Zn, Bi, Au, Co and combinations thereof It may include a second reaction layer containing the selected metal or alloy.

At least one layer of the first and second bonding metal layers is located between the first reaction layer and the second reaction layer and comprises a metal or alloy selected from the group consisting of Ti, W, Cr, Ta and combinations thereof. It may further include a reaction delay layer comprising.

According to another aspect of the present invention, there is provided a light emitting stack in which a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer are sequentially formed on a temporary substrate, and a first junction metal layer is formed on the light emitting laminate. Forming a second bonding metal layer on the permanent substrate, disposing the light emitting laminate on the permanent substrate so as to contact the first bonding metal layer and the second bonding metal layer; Reacting a junction metal layer with the second junction metal layer to form a eutectic metal junction layer such that the light emitting laminate and the permanent substrate are bonded to each other, and removing the semiconductor growth substrate from the light emitting laminate; At least one of the first junction metal layer and the second junction metal layer has an antioxidant film formed on an upper surface thereof, and the antioxidant film has a corresponding junction located thereunder. Provided is a method of manufacturing a semiconductor light emitting device made of a metal or an alloy having lower oxidation reactivity than a metal layer.

At least one layer of the first and second bonding metal layers may further include a reaction delay layer made of a metal or an alloy to delay a reaction between the first and second bonding metal layers.

The generation of voids in the eutectic metal bonding layer obtained by the reaction of the bonding metal between the two bonding objects can be effectively suppressed to maintain the high bonding strength, and can be advantageously used for the transfer technology of electronic devices such as semiconductor light emitting devices. Can be. In particular, it is possible to greatly suppress the generation of voids that can easily occur in the eutectic metal bonding layer in the case of the non-flat surface in which the uneven or stepped structure exists in the joint surface.

When the anti-oxidation film is applied to the surface of the bonded metal layer, the surface oxidation of the bonded metal layer is prevented from oxidizing before or during the bonding process, thereby solving the problem of lowering the bonding strength due to the surface oxidation and ensuring reliable bonding strength. Can be.

1A and 1B are cross-sectional views illustrating an example of a metal bonding layer forming method according to an aspect of the present invention.
2 and 3 are photographs taken in cross section of the metal bonding layer formed by the first embodiment and the comparative example.
4 is a photograph for confirming the distribution of the reaction layer in the metal bonding layer obtained in the first embodiment.
5 is a photograph of a cross section of the metal bonding layer obtained according to the second embodiment (change depending on the thickness of the reaction delay layer).
Figure 6 is a cross-sectional view showing a eutectic metal layer used in the metal bonding layer forming method according to an example of the present invention (reaction delay layer).
7A to 7C are cross-sectional views illustrating various examples of the metal bonding layer that may be formed by the reaction of the bonding metal layer shown in FIG.
8 is a cross-sectional view showing a joining metal layer used in the method for forming a metal joining layer according to an example (reaction delay layer) of the present invention.
9A to 9D are cross-sectional views showing various examples of the metal bonding layer that can be formed by the reaction of the bonding metal layer shown in FIG.
10A to 10D are cross-sectional views illustrating a method of manufacturing a semiconductor light emitting device according to another aspect of the present invention.
11A and 11B are a plan view and a cross-sectional side view showing another example of a semiconductor light emitting device that can be manufactured using the semiconductor light emitting device manufacturing method of the present invention, respectively.
12 is a cross-sectional view showing a eutectic metal layer used in the metal bonding layer forming method according to an example (antioxidation film) of the present invention.
13A and 13B are cross-sectional views showing various examples of the metal bonding layer that can be formed by the reaction of the bonding metal layer shown in FIG.
14 is a cross-sectional view showing a eutectic metal layer used in the metal bonding layer forming method according to an example (antioxidation film) of the present invention.
15A and 15B are cross-sectional views showing various examples of the metal bonding layer that can be formed by the reaction of the bonding metal layer shown in FIG.
16 is a cross-sectional view showing a eutectic metal layer used in the method for forming a metal bonding layer according to an example of the present invention (reaction delay layer + antioxidant film).
17A and 17B are cross-sectional views showing various examples of the metal bonding layer that can be formed by the reaction of the bonding metal layer shown in FIG.
18 is a cross-sectional view showing a eutectic metal layer used in the method for forming a metal bonding layer according to an example of the present invention (reaction delay layer + antioxidant film).
19A and 19B are sectional views showing various examples of the metal bonding layer that can be formed by the reaction of the bonding metal layer shown in FIG.
20A to 20D are cross-sectional views illustrating a method of manufacturing a semiconductor light emitting device according to another aspect of the present invention.
21A to 21D are cross-sectional views illustrating another example of a method of manufacturing a semiconductor light emitting device according to another aspect of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Shape and size of the elements in the drawings may be exaggerated for more clear description.

1A and 1B are cross-sectional views illustrating an example of a metal bonding layer forming method according to an aspect of the present invention.

Referring to FIG. 1A, there are shown first and second substrates 11 and 21 having one surface on which first and second bonding metal layers 12 and 22 are formed, respectively, as a bonding object.

In this example, the connection object is illustrated as a substrate, but not only a substrate as a substrate but also a substrate on which an electronic circuit for performing a specific function is implemented, as well as electronic devices such as semiconductor light emitting devices and memory devices It may be a connection object that can be applied.

The first and second junction metal layers 12 and 22 may each include a metal or an alloy selected from the group consisting of Sn, In, Zn, Bi, Pb, Ni, Au, Pt, Cu, Co, and combinations thereof. .

Specifically, as shown in FIG. 1A, the first bonding metal layer 12 is formed on the first reaction layer 12a and the first reaction layer 12a formed on one surface of the first substrate 11. The second reaction layer 12b may be included. Similarly, the second bonding metal layer 22 also includes the first reaction layer 22a formed on one surface of the second substrate 21 and the second reaction layer 22b formed on the first reaction layer 22a. It includes.

The first reaction layers 12a and 22a and the second reaction layers 12b and 22b may be formed of one or two or more metals or alloys that react with each other to form a eutectic metal. Although not limited thereto, the second reaction layers 12b and 22b may be formed of a metal or an alloy having a diffusion coefficient relatively larger than that of the first reaction layers 12a and 22a, and the first reaction layer 12a may be used. 22a may serve to maintain an adhesion state between the first and second substrates 11 and 21 and the first and second bonding metal layers 12 and 22.

For example, the first reaction layers 12a and 22a may include at least one metal of Ni, Pt, and Cu. The second reaction layers 12b and 22b may include a metal or an alloy selected from the group consisting of Sn, In, Zn, Bi, Au, Co, and combinations thereof.

In the present embodiment, as illustrated in FIG. 1A, the first bonding metal layer 12 may include a reaction delay layer that delays a reaction generated in the bonding process between the first and second reaction layers 12a and 12b. 15). That is, the reaction delay layer 15 plays a role of suppressing fluidity that is transferred to the molten metal to react with other metals or alloys in the bonding process of melting the first and second bonding metal layers 12a and 12b. . The reaction delay layer 15 may have a relatively low diffusion coefficient than the reactants constituting the first and second junction metal layers 12 and 22, or may be thermally or chemically stable compared to surrounding reactants. High metal materials can be used.

For example, the reaction delay layer 15 may include a metal or an alloy selected from the group consisting of Ti, W, Cr, Ta, and combinations thereof. The thickness of the reaction delay layer 15 may be 10 kPa to 1000 kPa.

As shown in FIG. 1A, the second substrate 21 is disposed on the first substrate 11 so that the first bonding metal layer 12 and the second bonding metal layer 22 face each other, and bonding is performed. Add condition for For example, constant heat is applied to melt the first and second bonding metal layers 12 and 22.

FIG. 1B illustrates a state in which the first and second substrates 11 and 21 are bonded by a eutectic metal bonding layer EM formed by melting the first and second bonding metal layers 12 and 22.

In the molten state, the second reaction layer 12b, 22b reacts with the first reaction layer 12a, 22a with high fluidity, as a result. As shown in FIG. 1B, a eutectic metal layer R formed as a result of the reaction between the first reaction layers 12a and 22a and the second reaction layers 12b and 22b is formed so that the eutectic metal bonding layer EM is highly bonded. May have strength. In some cases, some of the first reaction layers 12a 'and 22a' may remain unreacted, and the remaining first reaction layers 12a 'and 22a' may be formed of the first and second substrates 11. And 21) to maintain adhesion.

In the present embodiment, the reaction delay layer 15 may reduce the fluidity of the second reaction layers 12b and 22b, thereby delaying the reaction with the first reaction layers 12a and 22a. In the eutectic metal reacted in such a delay process, it is possible to have a high filling rate by reducing the generation of voids therein.

Specifically, the molten Sn layer, the SnAu layer, or the like used as the second reaction layer 12b, 22b may be another reaction layer (Ni layer, Pt layer, or Cu layer, such as the first reaction layer 12a, 12b). ) To form a eutectic metal bonding layer that is NiSn, NiSnAu, PtSnAu, or CuSn. In this process, fluidity of the molten Sn layer is reduced. As a result, the Sn layer, the SnAu layer, the NiSn layer, the NiSnAu layer, the PtSnAu layer, and the CuSn layer do not have sufficient time to fill the step formed on the bonding surface of the semiconductor layer or the substrate. As a result, voids may be formed on the bonding surface of the semiconductor layer and the substrate.

In order to solve this problem, in the present embodiment, the reaction delay layer is positioned between the two reaction layers to delay the reaction, and as a result, void generation can be suppressed by maintaining fluidity for a sufficient time.

Therefore, in the case where the joining surfaces of the first and second substrates of the joining object have uneven surfaces (step structures or irregularities), the eutectic metal bonding layer having a high bonding strength by ensuring a high level of filling with such a reaction delay. (EM) can be obtained.

Hereinafter, the operation and effects of the reaction delay layer employed in the present invention will be described with reference to the following examples.

< Example 1 >

In the epitaxial layer (wafer level) where the GaN light emitting device A1 having a constant step S is formed, a Ni layer and a SnAu layer (first junction metal layer) are formed as first and second reaction layers, respectively, and the silicon substrate ( Ni layer and SnAu layer (second junction metal layer) were formed in B1) similarly as a 1st and 2nd reaction layer. However, a 50 nm Ti film was introduced into the first junction metal layer as a reaction delay layer between the Ni layer and the SnAu layer.

Subsequently, heat was applied so that the GaN light emitting element and the silicon substrate were joined by the first and second bonding metal layers to form a eutectic metal bonding layer.

< Comparative Example 1 >

Similar to the first embodiment, the Ni layer and the SnAu layer (first junction metal layer) as first and second reaction layers in the epitaxial layer (wafer level) of the GaN light emitting device A2 having a constant step S, respectively. And a Ni layer and a SnAu layer (second junction metal layer) were formed on the silicon substrate B2 as the first and second reaction layers in the same manner. However, unlike Example 1, no reaction delay layer was introduced.

Subsequently, heat was applied to the GaN light emitting device and the silicon substrate by the first and second bonding metal layers to form a eutectic metal bonding layer.

Photographs taken in cross section of the eutectic metal bonding layer formed by Example 1 and Comparative Example 1 are shown in FIGS. 2 and 3, respectively.

As shown in FIG. 2, the eutectic metal bonding layer EM according to Example 1 shows a region in which a reaction is locally generated, and although the GaN light emitting device A1 has a step S, Although no void was found, as shown in FIG. 3, in the case of the eutectic metal bonding layer EM according to Comparative Example 1, the reaction was shown to occur over a relatively wide area, and in particular, GaN light emitting device A1. It can be seen that the large void (V) is generated in the area immediately below the step (S) of the.

That is, in the case of Comparative Example 1, while the reaction between Ni and SnAu proceeds rapidly over a wide area, the void V is not generated in the non-flat surface such as step S, whereas Example V occurs. In the case of, the reaction between Ni and SnAu was delayed by the Ti reaction delay layer located between the two reaction layers, and thus it was possible to secure the time to be filled while maintaining high fluidity even on the non-flat surface having the step (S) structure. As a result, it was possible to greatly suppress the generation of voids.

In this regard, referring to FIG. 4, it can be seen that there is less NiSnAu eutectic metal, which is a reaction product, in the region located in the Ti reaction delay layer. As such, the Ti reaction delay layer suppressed the reaction between Ni and SnAu to maintain relatively long time fluidity, and as a result, voids could be uniformly filled even in the bent portion of the GaN light emitting device A1. .

As described above, even in a bonding object having a non-flat surface such as a stepped structure, the eutectic metal bonding layer having a high filling rate can be provided by delaying the reaction between the bonding metal layers using the reaction delay layer, thereby having a high bonding strength.

In addition, an experiment (Example 2 and Comparative Example 2) was performed to examine the reaction delay effect according to the thickness of the reaction delay layer.

< Example 2 A, 2B>

Similar to the first embodiment, a Ni layer and a SnAu layer (first junction metal layer) are respectively formed as first and second reaction layers on the epitaxial layers of GaN light emitting devices A4 and A5 having a constant step S. Then, a Ni layer and a SnAu layer (second junction metal layer) were formed on the silicon substrate B1 as the first and second reaction layers in the same manner. In addition, a Ti film was introduced into the first junction metal layer as a reaction delay layer between the Ni layer and the SnAu layer.

However, two samples 2A and 2B were prepared by varying the thickness of the Ti film to 50 mW and 300 mW, respectively.

Subsequently, heat was applied so that the GaN light emitting device and the silicon substrate were joined by the first and second bonding metal layers to form a eutectic metal bonding layer.

< Comparative Example 2 >

Similar to the previous embodiments, a Ni layer and a SnAu layer (first junction metal layer) are formed on the epitaxial layer of the GaN light emitting device A3 having a constant step S as first and second reaction layers, respectively. The Ni layer and the SnAu layer (second junction metal layer) were formed in the silicon substrate B3 as the first and second reaction layers in the same manner. However, no Ti film was introduced in either of the first and second bonding metal layers.

Subsequently, heat was applied so that the GaN light emitting device and the silicon substrate were joined by the first and second bonding metal layers to form a eutectic metal bonding layer.

5A to 5C are photographs taken in cross section of the eutectic metal bonding layer obtained in Comparative Example 2, Example 2A and Example 2B, respectively.

As shown in Fig. 5A, when no Ti film is employed (Comparative Example 2), it can be seen that a large void is formed. Such large voids may greatly degrade the bonding strength and significantly reduce the reliability of the device.

On the other hand, when the Ti film is 50 microseconds (Example 2A), as shown in FIG. 5B, only a very small void V is found, and when the Ti film is 300 microseconds (Example 2B), it is shown in FIG. 5C. As such, no voids were found.

As such, as the thickness of the Ti film, which is the reaction delay layer, increased, the degree of reaction delay increased, and it was confirmed that a higher level of filling was possible. However, in order to avoid a case in which the reaction delay is excessively large or the reaction itself is suppressed, the thickness of the reaction delay layer may be adjusted according to the bonding metal system. In view of this, it is preferable not to exceed 1000 mW. On the other hand, for the effect of the reaction delay, it is desirable to have a thickness of at least 10 kPa.

Hereinafter, examples of various bonding metal systems that can be implemented using the reaction delay layer will be described. 6-9 illustrate the structure of the bonding metal layer and the structure of the eutectic metal bonding layer that can be obtained as a result of the construction material.

First, referring to FIG. 6, first and second substrates 111 and 121 having one surface on which first and second bonding metal layers 112 and 122 are formed, respectively, are shown as a bonding object.

The first junction metal layer 112 may include a first reaction layer 112a formed on one surface of the first substrate 111 and a second reaction layer 112b formed on the first reaction layer 112a. have. Similarly, the second bonding metal layer 122 also has a first reaction layer 122a formed on one surface of the second substrate 121 and a second reaction layer 122b formed on the first reaction layer 122a. It includes. In addition, unlike the form illustrated in FIG. 1A, the reaction delay layers 115 and 125 are formed on both the first and second bonding metal layers 112 and 122.

In this example, the second reaction layers 112b and 122b may be Sn or AuSn. In this case, the first reaction layers 112a and 122a may be Ni. In addition to Ni, Pt, Au, Cu, or Co may be used as the first reaction layer. The reaction delay layers 115 and 125 may be Ti films.

As described above, the reaction delay layers 115 and 125, which are Ti, may sufficiently secure fluidity by delaying the reaction process performed in the bonding process. As a result, it is possible to provide a bonding system having a desired level of filling rate and excellent reliability.

7A-7C illustrate a eutectic metal bonding layer (EM) structure that can be obtained using the first and second bonding metal layers illustrated in FIG.

As shown in FIG. 7A, a mixed layer R11 including a eutectic metal made of NiSn or NiSn / Sn / NiSn (or NiSnAu when the first reaction layer is AuSn) is formed in the center region, and the mixed layer R11 is formed. ) Ti layers 115 ′ and 125 ′ are positioned as residues of the reaction delay layers 115 and 125. The remaining Ti layers 115 'and 125' may be present in a somewhat deformed form (bent or partially disconnected) during the reaction. Ni layers 112a ′ and 122a ′ may remain between the Ti layers 115 ′ and 125 ′ and the first and second substrates 111 and 121.

In another embodiment, as shown in FIG. 7B, a first mixed layer R11 including a eutectic metal made of NiSn or NiSn / Sn / NiSn (or NiSnAu when the first reaction layer is AuSn) is formed in a central region. Ti layers 115 ′ and 125 ′ are positioned around the first mixed layer R11. In addition, Sn is also diffused on the Ti layer 115 'on one side to form NiSn or NiAuSn, which is the second mixed layer R12. In the bonding system of this embodiment, Ni layers 112a 'and 122a' may still remain at the interface with the first and second substrates 111 and 121.

As shown in FIG. 7C, a first material including a eutectic metal made of NiSn or NiSn / Sn / NiSn (or NiSnAu when the first reaction layer is AuSn) is formed in a central region of another type of eutectic metal bonding layer EM. 1 The mixed layer R11 may be formed. Ti layers 115 ′ and 125 ′ are positioned around the first mixed layer R11, and unlike the previous example, the second mixed layers R12 and R12 that are NiSn or NiAuSn react with little Ni layers remaining, unlike the previous example. ') Can be provided.

As such, even when the same bonding metal layer shown in FIG. 6 is used, it may have a shared metal bonding layer (EM), which is a bonding system of various types, as shown in FIGS. 7A to 7C according to a bonding process that is actually applied. Meanwhile, the covalent metal bonding layer EM shown in FIGS. 7A to 7C may be understood as a series of processes in which a reaction process is performed with diffusion in the order shown.

A structure having a joining metal layer according to another example is shown in FIG. Referring to FIG. 8, there are shown first and second substrates 211 and 221 having one surface on which first and second bonding metal layers 212 and 222 are formed, respectively.

The first bonding metal layer 212 may include a first reaction layer 212a formed on one surface of the first substrate 211 and second reaction layers 212b and 212c having a multilayer structure formed on the first reaction layer 212a. ) May be included. Similarly, the second bonding metal layer 222 also has a first reaction layer 222a formed on one surface of the second substrate 221 and a second reaction layer having a multilayer structure formed on the first reaction layer 222a. (222b, 222c).

In this example, the second reaction layer of the multilayer structure may be Au layers 212c and 222c and Sn layers 212b and 222b sequentially stacked, respectively.

Reaction delay layers 215 and 225 employed in this example are provided on both the first and second bonding metal layers 212 and 222, and are formed between the first reaction layers 212a and 222a and the Au layers 212c and 222c, respectively. do.

The first reaction layers 212a and 222a may be Ni. In addition to Ni, Pt, Au, Cu, or Co may be used as the first reaction layers 212a and 222a. The reaction delay layers 215 and 225 are both employed as Ti films. Of course, the reaction delay layers 215 and 225 may be, in addition to Ti, W, Cr, Ta and combinations thereof.

9A-9D illustrate a eutectic metal bonding layer (EM) structure obtained using the first and second bonding metal layers illustrated in FIG. 8.

As shown in FIG. 9A, a mixed layer R21 including a eutectic metal made of NiSnAu is formed in a central region, and Ti layers 215 'and 225' are positioned around the mixed layer R21. The remaining Ti layers 215 'and 225' may be present in a somewhat deformed form (bent or partially disconnected) during the reaction. Ni layers 212a ′ and 222a ′ may remain between the Ti layers 215 ′ and 225 ′ and the first and second substrates 211 and 221.

In another embodiment, as shown in FIG. 9B, a first mixed layer R21 including a eutectic metal made of NiSnAu is formed in the center region of the eutectic metal bonding layer EM, and Ti is formed around the first mixed layer R21. Layers 215 ', 225' remain. Sn may also diffuse to one side of the remaining Ti layer 215 'to form NiSnAu, which is the second mixed layer R22. Even in the bonding system of this embodiment, Ni layers 212a 'and 222a' may remain at the interface with the first and second substrates 211 and 221.

As shown in FIG. 9C, in another type of eutectic metal bonding layer EM, a first mixed layer R21 including a eutectic metal made of NiSnAu is formed in a central region thereof, and around the first mixed layer R21. The second mixed layers R22 and R22 ', which are NiSnAu, may be formed around the Ti layers 215' and 225 'which remain while the Ti layers 215' and 225 'remain. Also, in the eutectic metal bonding layer EM of the present embodiment, Ni layers 212a 'and 222a' may remain at the interface with the first and second substrates 211 and 221.

In another embodiment of the eutectic metal bonding layer EM, as shown in FIG. 9D, a first mixed layer R21 including a eutectic metal made of NiSnAu is formed in a central region, and around the first mixed layer R21. When the Ti layers 215 'and 225' are positioned, all of the Ni layers with little Ni residue remaining thereon may be reacted to provide second mixed layers R22 and R22 'that are NiSnAu.

As such, even if the same bonding metal layer shown in FIG. 8 is used, it may have a eutectic metal bonding layer EM, which is a bonding system of various types, as shown in FIGS. 9A to 9D according to the bonding process applied in practice. Meanwhile, the eutectic metal bonding layer EM shown in FIGS. 9A to 9D may be understood as a series of processes in which a reaction process is performed with diffusion in the order shown.

In this example, unlike the structure of the second reaction layer described in FIG. 8, the Au layer and the Sn layer may be reversed in the stacking order. Even with such a change, it may have a metal bonding layer similar in shape to the eutectic metal bonding layer EM shown in FIGS. 9A to 9D.

The various types of bonding systems described above can be advantageously used to bond electronic devices, such as semiconductor light emitting devices, to a substrate. As an example, a method of manufacturing a semiconductor light emitting device using the above-mentioned eutectic metal bonding layer is illustrated in FIGS. 10A to 10D.

10A to 10D are cross-sectional views illustrating a method of manufacturing a semiconductor light emitting device according to another aspect of the present invention.

Referring to FIG. 10A, a light emitting stack is prepared by sequentially growing a first conductive semiconductor layer 702, an active layer 703, and a second conductive semiconductor layer 704 on a growth substrate 701.

Such a growth process may use, for example, a MOCVD or MBE deposition process. The light emitting laminate is a group III-V semiconductor, in particular a group III nitride semiconductor (Al _x Ga _y In _(1-xy) N (0≤x≤1, 0≤y≤1, 0≤x + y≤1)) It may be made of. The substrate 701 for growing the nitride semiconductor crystal may be sapphire, SiC, Si, MgAl ₂ O ₄ , MgO, LiAlO ₂ or LiGaO ₂ .

Next, as shown in FIG. 10B, a first bonding metal layer 712 is formed on the light emitting stack (particularly, the second conductivity type semiconductor layer 704), and the first bonding metal layer 712 is formed on the bonding surface of the permanent substrate 721. 2 joining metal layer 722 is formed.

The permanent substrate 721 may be a conductive substrate. For example, the permanent substrate 721 may be a Si substrate or a Si-Al alloy substrate. The first and second bonding metal layers 712 and 722 may include reaction delay layers 715 and 725, respectively. The first and second junction metal layers 712 and 722 may include first reaction layers 712a and 722a and second reaction layers 712b and 722b that may react with each other to form a eutectic metal. 715 and 725 are positioned between the first reaction layers 712a and 722a and the second reaction layers 712b and 722b.

The first reaction layers 712a and 722a are layers for connecting the permanent substrate 721 to be bonded to the light emitting stack and may include at least one metal of Ni, Pt, Au, Cu, and Co. The second reaction layers 712b and 722b may include a metal or an alloy selected from the group consisting of Sn, In, Zn, Bi, Au, Co, and combinations thereof.

The reaction delay layers 715 and 725 may include a metal or an alloy selected from the group consisting of Ti, W, Cr, Ta, and combinations thereof. The reaction delay layers 715 and 725 may have a thickness of 10 kPa to 1000 kPa.

Subsequently, the permanent substrate 721 is disposed on the second conductivity type semiconductor layer 704 so that the first and second junction metal layers 712 and 722 face each other, and heat is applied to the first and second junction metal layers ( 712,722 melt to form the desired eutectic metal bonding layer EM. While the molten second reaction layers 712b and 722b flow to react with the first reaction layers 712a and 722a to form a eutectic metal, the reaction is applied to the reaction delay layers 715 and 725 employed in the present example. Can be delayed to ensure sufficient flow time. As a result, a high filling rate (i.e., suppressing the generation of voids in the eutectic metal) can be obtained over the entire bonding area.

Next, as shown in FIG. 10C, the growth substrate 701 may be separated from the first conductivity type semiconductor layer 702. This separation process may be performed by irradiating a laser to the interface between the growth substrate 701 and the first conductivity-type semiconductor layer 702.

Next, as illustrated in FIG. 10D, the first electrode 707 is formed on the surface of the first conductivity-type semiconductor layer 702 exposed by the separation of the growth substrate 701. If necessary, a bonding electrode may be further formed on an opposite surface of the permanent substrate 721.

Thus, even when the bonding surface of the light emitting laminate or the bonding surfaces of the permanent substrates 715 and 725 have a structure such as a step or unevenness, void generation can be effectively suppressed to form a solid eutectic metal bonding layer EM, and the bonding reliability. Can greatly improve.

The method of manufacturing a semiconductor light emitting device may be usefully applied to other semiconductor light emitting devices having various structures. 11A and 11B are a plan view and a side cross-sectional view showing an example of a semiconductor light emitting device that can be manufactured using the method of manufacturing a semiconductor light emitting device of the present invention.

As shown in FIGS. 11A and 11B, the semiconductor light emitting device 800 may include a conductive substrate 810, a first electrode layer 820, an insulating layer 830, a second electrode layer 840, and a second permanent substrate. The conductive semiconductor layer 804, the active layer 803, and the first conductive semiconductor layer 802 are included. For example, the first conductivity type semiconductor layer 802 may be an n-type nitride semiconductor, and the second conductivity type semiconductor layer 804 may be a p-type nitride semiconductor.

The first electrode layer 820 is stacked on the conductive substrate 810. In addition, the contact penetrates through the insulating layer 830, the second electrode layer 840, the second conductive semiconductor layer 804, and the active layer 803 to a predetermined region of the first conductive semiconductor layer 802. Hole 880 is formed. A portion of the first electrode layer 820 contacts the first conductivity type semiconductor layer 802 through the contact hole 880 as shown in FIG. 11B. Thus, the conductive substrate 810 and the first conductivity type semiconductor layer 802 may be electrically connected.

As such, the first electrode layer 820 may electrically connect the conductive substrate 810 and the first conductivity-type semiconductor layer 802 through the contact hole 880.

Meanwhile, the semiconductor light emitting device 800 includes the insulating layer 830 such that the first electrode layer 820 is electrically insulated from other layers except for the conductive substrate 810 and the first conductive semiconductor layer 802. It is provided. The insulating layer 830 is not only between the first electrode layer 820 and the second electrode layer 840, but also the second electrode layer 840 and the second conductivity type semiconductor layer exposed by the contact hole 880. 804 and also between the active layer 803 and the first electrode layer 820.

The second electrode layer 840 is positioned to be connected to the second conductive semiconductor layer. The second electrode layer 840 may include any one metal of Ag, Al, and Pt in consideration of ohmic contact and reflectance. In addition, the second electrode layer 840 has a region 845 exposed to the outside as shown in FIG. 11A, and the electrode pad 846 may be provided with an external power source on the exposed region 845. In the present embodiment, one exposed area 815 and one electrode pad 846 are illustrated, but one or more exposed areas may be provided.

As shown in FIG. 11B, the semiconductor light emitting device 800 may be obtained by forming a common metal bonding layer EM between the conductive substrate 810 and the first electrode layer 820. The light emitting laminate may be bonded onto the conductive substrate 810 by using the formation process of the common metal bonding layer EM described above.

That is, the eutectic metal bonding layer (EM) may be a eutectic metal obtained by reacting the molten metal or alloy with each other, and may include Sn, In, Zn, Bi, Pb, Ni, Au, Pt, Cu, Co, and combinations thereof. It may be a eutectic metal comprising a metal or alloy selected from the group consisting of.

In addition, the eutectic metal bonding layer (EM) may include a reaction delay layer (815). The reaction delay layer 815 may be a metal or an alloy selected from the group consisting of Ti, W, Cr, Ta, and combinations thereof. The reaction delay layer 815 may delay the reaction process of forming a common metal at the time of bonding.

In the final result, the reaction delay layer 815 is deformed during the reaction process to form a eutectic metal, it may not be a complete layer structure. For example, the remaining reaction delay layer 815 may be present in the form of a discontinuous or non-uniform thickness.

The present invention provides a method of maintaining the surface of the bonding metal layer in an advantageous state for bonding, in addition to delaying the reaction process by introducing a reaction delay layer into the bonding metal layer. Specifically, by introducing an antioxidant film so that the surface of the bonding metal layer is not oxidized, the strength of the eutectic metal bonding layer can be prevented from being lowered by an unwanted oxide. This embodiment will be described with reference to FIGS. 12 to 15.

12 is a cross-sectional view showing a eutectic metal bonding layer used in the metal bonding layer forming method according to an example (antioxidation film) of the present invention.

Referring to FIG. 12, first and second substrates 111 and 121 having one surface on which first and second bonding metal layers 112 and 122 are formed are shown.

Similar to the previous embodiment (especially, the example shown in FIG. 6), the first and second bonding metal layers 112 and 122 are formed on the first reaction layer 112a and the first and second substrates 111 and 112, respectively. 122a) and second reaction layers 112b and 122b formed on the first reaction layers 112a and 122a. In this example, the second reaction layers 112b and 122b may be Sn or AuSn. In this case, the first reaction layers 112a and 122a may be Ni. In addition to Ni, the first reaction layers 112a and 122a may be Pt, Au, Cu, or Co.

In addition, the first and the first bonding metal layers 112 and 122 may include antioxidant films 118 and 128 formed on the bonding surface thereof. In this example, the antioxidant layers 118 and 128 may be formed on the second reaction layers 112b and 122b as cap layers.

The anti-oxidation layers 118 and 128 are different from those of the corresponding metal layer located below or during the bonding process, and are introduced to prevent the metal layer material from being oxidized. In this example, the anti-oxidation layers 118 and 128 may be a material having a lower oxidation reactivity than the material of the second reaction layers 112b and 122b. For example, the antioxidant layers 118 and 128 may be selected from the group consisting of Pd, Pt, Ru, Rh, Ag, Os, Ir, Au, and combinations thereof. Preferably, the antioxidant layers 118 and 128 may be Pd, Pt, or a combination thereof.

Although not limited thereto, the anti-oxidation layers 118 and 128 may be positioned on the surface to be bonded, and may have an appropriate thickness so as not to substantially prevent a reaction between the bonding metal layers.

For example, the thickness t of the antioxidant films 118 and 128 may be 100 kW or less. In addition, in order to sufficiently obtain the antioxidant effect, the thickness t of the antioxidant films 118 and 128 may be 5 GPa or more, preferably 10 GPa or more.

13A and 13B illustrate a eutectic metal bonding layer (EM) structure that can be obtained using the first and second bonding metal layers 112 and 122 illustrated in FIG.

As shown in FIG. 13A, a mixed layer R31 including a eutectic metal made of NiSn or NiSn / Sn / NiSn (or NiSnAu when the first reaction layer is AuSn) may be formed. Since the antioxidant films 118 and 128 are introduced at a relatively thin thickness, they may be distributed in the mixed layer R31 without remaining as a layer. Ni layers 112a 'and 122a' may remain between the mixed layer R31 and the first and second substrates 111 and 121.

As shown in FIG. 13B, in another type of covalent metal bonding layer EM, a mixed layer R31 including a eutectic metal made of NiSn (or NiSnAu when the first reaction layer is AuSn) may be formed. Unlike the previous example, the mixed layer R11 may be provided as NiSn or NiAuSn by reacting with little remaining Ni layer.

As such, even if the same bonding metal layer shown in FIG. 12 is used, it may have a shared metal bonding layer EM, which is a bonding system of various types, as shown in FIGS. 13A and 13B according to the bonding process applied in practice. Meanwhile, the eutectic metal bonding layer shown in FIGS. 13A and 13B may be understood as a series of processes in which a reaction process is performed with diffusion in the order shown.

As another example of employing the antioxidant film, a description will be given with reference to the bonding metal layer shown in FIG.

Referring to FIG. 14, there are shown first and second substrates 311 and 321 having one surface on which first and second bonding metal layers 312 and 322 are formed, respectively.

The first bonding metal layer 312 may include a reaction layer 312a formed on one surface of the first substrate 311. In contrast, the second bonding metal layer 322 may include a first reaction layer 322a formed on one surface of the second substrate 321 and a second reaction layer 322b formed on the first reaction layer 322a. It may include. In this example, the reaction layer 312a and the first reaction layer 322a may be Ni. In addition to Ni, it may be Pt, Au, Cu or Co. The second reaction layer 322b may be Sn.

A first antioxidant layer 318 may be formed on the surface of the first junction metal layer 312, and a second antioxidant layer 328 may be formed on the surface of the second junction metal layer 322. As the cap layer, the first and second antioxidant films 318 and 328 may be employed to prevent the first and second bonding metal layers 312 and 322 from being oxidized.

The first antioxidant layer 318 may be a material having a lower oxidation reactivity than the material of the reaction layer 312a, and the second antioxidant layer 328 may be more oxidation-reactive than the material of the second reaction layer 322b. It may be a low material. The first and second antioxidant films 318 and 328 may be selected from the group consisting of Pd, Pt, Ru, Rh, Ag, Os, Ir, Au, and combinations thereof. Preferably, the first and second antioxidant layers 318 and 328 may be Pd, Pt, or a combination thereof. The first and second antioxidant films 318 and 328 may be made of the same material.

Although not limited thereto, the first and second antioxidant films 318 and 328 may have a thickness for obtaining a sufficient effect without substantially disturbing the reaction between the bonding metal layers. For example, the first and second antioxidant films 318 and 328 may have a thickness in the range of 10 to 100 kPa. In the above embodiment, the anti-oxidation film is formed on both surfaces of the bonding metal layer on both sides, but even if formed on only one surface of the bonding metal layer on both sides can be expected to prevent the surface oxidation.

15A and 15B illustrate a eutectic metal bonding layer (EM) structure obtained using the first and second bonding metal layers 312 and 322 illustrated in FIG.

In the eutectic metal bonding layer EM shown in FIG. 15A, a mixed layer R31 including a eutectic metal made of NiSn or NiSn / Sn / NiSn (or NiSnAu when the second reaction layer is AuSn) is formed. Can be. Ni layers remaining between the mixed layer R31 and the first and second substrates 311 and 321 may exist. Since the antioxidant films 318 and 328 are introduced at a relatively thin thickness, they may be distributed in the mixed layer R31 without remaining as a layer.

The eutectic metal bonding layer EM shown in FIG. 11B may be formed almost exclusively of the mixed layer R31. That is, there is a difference from the eutectic metal bonding layer (EM) structure shown in Fig. 11A in that an almost unreacted Ni layer remains around the mixed layer R31.

Unlike the above-described example, if necessary, the bonding metal layer may include a reaction delay layer together with the antioxidant film. This example is shown in FIGS. 16 and 18.

Referring to FIG. 16, there are shown first and second substrates 311 and 321 having one surface on which first and second bonding metal layers 312 and 322 are formed, respectively, as a bonding object.

The first bonding metal layer 312 may include a reaction layer 312a formed on one surface of the first substrate 311. In contrast, the second bonding metal layer 322 may include a first reaction layer 322a formed on one surface of the second substrate 321 and a second reaction layer 322b formed on the first reaction layer 322a. It may include. In this example, the reaction layer 312a and the first reaction layer 322a may be Ni. In addition to Ni, it may be Pt, Au, Cu or Co. The second reaction layer 322b may be Sn.

A first antioxidant layer 318 may be formed on the surface of the first junction metal layer 312, and a second antioxidant layer 328 may be formed on the surface of the second junction metal layer 322. As the cap layer, the first and second antioxidant films 318 and 328 may be employed to prevent the first and second bonding metal layers 312 and 322 from being oxidized.

The first antioxidant layer 318 may be a material having a lower oxidation reactivity than the material of the reaction layer 312a, and the second antioxidant layer 328 may be more oxidation-reactive than the material of the second reaction layer 322b. It may be a low material. The first and second antioxidant films 318 and 328 may be selected from the group consisting of Pd, Pt, Ru, Rh, Ag, Os, Ir, Au, and combinations thereof. Preferably, the first and second antioxidant layers 318 and 328 may be Pd, Pt, or a combination thereof. The first and second antioxidant films 318 and 328 may be made of the same material.

Unlike the previous example, in the present example, the second junction metal layer 322 may further include a reaction delay layer 325. The reaction delay layer 325 may be formed between the first reaction layer 322a and the second reaction layer 322c. The reaction delay layer 325 may be Ti, but is not limited thereto. In addition to Ti, W, Cr, Ta, and combinations thereof may be used.

17A and 17B illustrate a eutectic metal bonding layer (EM) structure obtained using the first and second bonding metal layers illustrated in FIG.

As shown in FIG. 17A, mixed layers R31 and R32 may be formed around the Ti layer 325 ′, which is a reaction delay layer. The mixed layers R31 and R32 may be NiSn containing a small amount of elements (eg, Pt or Pd) of the antioxidant layers 318 and 328. Ni layers 312a 'and 322a' may remain around the mixed layers R31 and R32.

In another embodiment, as illustrated in FIG. 17B, mixed layers R31 and R32 may be formed around the Ti layer 325 ′, which is a reaction delay layer. The mixed layers R31 and R32 may be NiSn containing a small amount of elements (eg, Pt or Pd) of the antioxidant layers 318 and 328. It is different from the eutectic metal bonding layer (EM) structure shown in Fig. 17A in that almost all of the Ni layer reacts and hardly remains.

As such, even if the same bonding metal layer shown in FIG. 16 is used, it may have a eutectic metal bonding layer EM, which is a bonding system of various types, as shown in FIGS. 17A and 17B according to the bonding process applied in practice. Meanwhile, the eutectic junction metal layer shown in FIGS. 17A and 17B may be understood as a series of processes in which the reaction process proceeds with diffusion.

Referring to FIG. 18, first and second substrates 411 and 421 having one surface of which first and second bonding metal layers 412 and 422 are formed, respectively, are shown as bonding objects.

In the present embodiment, unlike the previous example (Fig. 16), the joining metal layers formed on both joining objects have a symmetrical structure. That is, the first junction metal layer 412 may include a first reaction layer 412a formed on one surface of the first substrate 411 and a second reaction layer 412b formed on the first reaction layer 412a; An anti-oxidation film 418 is formed on the second reaction layer 412b.

Similarly, the second bonding metal layer 422 may include a first reaction layer 422a formed on one surface of the second substrate 421 and a second reaction layer 422b formed on the first reaction layer 422a. And an anti-oxidation layer 428 formed on the second reaction layer 422b.

In this example, the first reaction layers 412a and 422a may be Ni. In addition to Ni, Pt, Au, Cu, or Co may be used as the first reaction layers 412a and 422a. The second reaction layers 412b and 422b may be Sn.

The antioxidant films 418 and 428 may be selected from the group consisting of Pd, Pt, Ru, Rh, Ag, Os, Ir, Au, and combinations thereof. Preferably, the antioxidant layers 418 and 428 may be Pd, Pt, or a combination thereof.

In addition, the reaction delay layers 415 and 425 are applied to both the first and second bonding metal layers 412 and 422. The reaction delay layers 415 and 425 may be Ti, and in addition to Ti, W, Cr, Ta, and combinations thereof may be used as necessary.

19A-19C illustrate a eutectic metal bonding layer (EM) structure obtained using the first and second bonding metal layers 412, 422 illustrated in FIG. 18.

As shown in Fig. 19A, a mixed layer R41 is formed in the center region. Here, the mixed layer R41 may be NiSn containing a small amount of elements (eg, Pt or Pd) of the antioxidant layers 412b and 422b. Ti layers 415 'and 425' remain around the mixed layer R41. As described above, the remaining Ti layers 415 ', 425' may be present in a somewhat deformed form (bent or partially disconnected) during the reaction. Ni layers 412a 'and 422a' may remain between the Ti layers 415 'and 425' and the first and second substrates 411 and 421.

In another embodiment, as shown in FIG. 19B, a first mixed layer R41 including a eutectic metal made of NiSn containing a small amount of elements (eg, Pt or Pd) of the antioxidant films 412b and 422b may be formed. have. Ti layers 415 'and 425' remaining around the first mixed layer R41 are positioned. Sn may also be diffused on the Ti layer 415 'on one side to form NiSn, which is the second mixed layer R42. In the common junction metal layer EM, Ni layers 412a 'and 422a' may remain at the interface with the first and second substrates 411 and 421.

In another type of bonding system, as shown in Fig. 19C, the first mixed layer R41 including a eutectic metal made of NiSn containing a small amount of elements (eg, Pt or Pd) of the antioxidant films 412b and 422b is Can be formed. Ti layers 415 'and 425' remaining around the first mixed layer R41 are positioned, and a second mixed layer R42, which is NiSn containing Pt or Pd around the Ti layers 415 'and 425', R 42 ′) may be formed. In the common bonding metal layer EM, the Ni layer may hardly remain around the second mixed layers R42 and R42 ', respectively.

As such, even if the same bonding metal layer shown in FIG. 18 is used, it may have a eutectic metal bonding layer EM, which is a bonding system of various types, as shown in FIGS. 19A to 19C according to the bonding process applied in practice. Meanwhile, the eutectic bonded metals shown in FIGS. 19A to 19C may be understood as a series of processes in which a reaction process is performed with diffusion in the order shown.

The various types of bonding systems described above can be advantageously used to bond electronic devices, such as semiconductor light emitting devices, to a substrate. As an example, a method of manufacturing a semiconductor light emitting device using the above-described eutectic metal bonding layer is illustrated in FIGS. 20A to 20D.

20A to 20D are cross-sectional views illustrating a method of manufacturing a semiconductor light emitting device according to another aspect of the present invention. This embodiment is similar to the form shown in Figs. 10A to 10D, and the same reference numerals can be understood as corresponding elements.

Referring to FIG. 20A, similarly to the form shown in FIG. 10A, the first conductive semiconductor layer 702, the active layer 703, and the second conductive semiconductor layer 704 are sequentially formed on the growth substrate 701. Growing to prepare a light emitting laminate.

Next, as shown in FIG. 20B, a first bonding metal layer 712 is formed on the light emitting stack (particularly, the second conductivity type semiconductor layer 704), and the first bonding metal layer 712 is formed on the bonding surface of the permanent substrate 721. 2 joining metal layer 722 is formed.

The first and second junction metal layers 712 and 722 include first reaction layers 712a and 722a and second reaction layers 712b and 722b that may react with each other to form a eutectic metal. Reaction delay layers 715 and 725 are disposed between the first reaction layers 712a and 722a and the second reaction layers 712b and 722b.

The first reaction layers 712a and 722a are layers for connecting the permanent substrate 721 to be bonded to the light emitting stack and may include at least one metal of Ni, Pt, Au, Cu, and Co. The second reaction layers 712b and 722b may include a metal or an alloy selected from the group consisting of Sn, In, Zn, Bi, Au, Co, and combinations thereof. The reaction delay layers 715 and 725 may include a metal or an alloy selected from the group consisting of Ti, W, Cr, Ta, and combinations thereof.

In addition, in the present embodiment, antioxidant films 718 and 728 are disposed on the surfaces of the first and second bonding metal layers 712 and 722 as cap layers, respectively. The anti-oxidation layers 718 and 728 may be a material having a lower oxidation reactivity than the material of the first reaction layers 712a and 722a provided on the surface thereof. For example, the antioxidant films 718 and 728 may be selected from the group consisting of Pd, Pt, Ru, Rh, Ag, Os, Ir, Au, and combinations thereof. Preferably, the antioxidant layers 718 and 728 may be Pd, Pt, or a combination thereof.

Although not limited thereto, the antioxidant films 718 and 728 may have a thickness for obtaining a sufficient effect without substantially hindering a reaction between the bonding metal layers. For example, the antioxidant films 718 and 728 may have a thickness in the range of 10 to 100 GPa.

Next, the permanent substrate 721 is disposed on the second conductivity type semiconductor layer 704 so that the first and second junction metal layers 712 and 722 face each other, and the first and second junction metal layers are applied by applying heat. 712 and 722 melt to form the desired eutectic metal bonding layer EM.

By suppressing generation of oxide films on the surfaces of the first and second bonding metal layers 712 and 722 before or during the connection, an advantageous bonding interface state can be obtained to obtain bonding strength. In addition, the reaction delay layers 715 and 725 may delay the reaction between the first reaction layers 712a and 722a and the second reaction layers 712b and 722b to ensure a high filling rate over the entire junction region.

Next, as shown in FIG. 20C, the growth substrate 701 may be separated from the first conductivity type semiconductor layer 702. This separation process may be performed by irradiating a laser to the interface between the growth substrate 701 and the first conductivity-type semiconductor layer 702.

Next, as shown in FIG. 20D, the first electrode 707 is formed on the surface of the first conductivity-type semiconductor layer 702 exposed by the separation of the growth substrate 701. If necessary, a bonding electrode may be further formed on an opposite surface of the permanent substrate 721.

In this way, by preventing the generation of oxides on the surface to be bonded and delaying the reaction rate to suppress the generation of voids, a solid eutectic metal bonding layer EM can be formed, and the bonding reliability can be greatly improved.

The method of manufacturing a semiconductor light emitting device may be usefully applied to semiconductor light emitting devices having various other structures. 21A to 21D show another example of a method applied to another semiconductor light emitting device.

21A, a semiconductor light emitting device having a structure different from that of the semiconductor light emitting device shown in FIG. 20A is shown.

The semiconductor light emitting device 910 shown in FIG. 21A includes a substrate 901 and a light emitting stack disposed on the substrate 901. The light emitting stack may include a first conductive semiconductor layer 902, an active layer 903, and a second conductive semiconductor layer 904.

The substrate 901 may be an insulating, conductive or semiconductor substrate. For example, the substrate 901 may be sapphire, SiC, Si, MgAl ₂ O ₄ , MgO, LiAlO ₂ , LiGaO ₂ , GaN. The surface of the substrate 901 may include a hemispherical uneven structure (P). The shape of the uneven structure P is not limited thereto, and may have other polyhedral structures or irregular shapes of irregularities.

Nitride satisfying the first conductive type semiconductor layer 902 is an n-type _{Al x In y Ga 1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) semiconductor The n-type impurity may be Si. For example, the first conductivity type semiconductor layer 902 may be n-type GaN. The active layer 903 may have a multi-quantum well (MQW) structure in which a quantum well layer and a quantum barrier layer are alternately stacked, for example, a nitride semiconductor, and a GaN / InGaN structure. Of course, the active layer 903 may have a single quantum well (SQW) structure. The second conductive type semiconductor layer 904 may be a nitride semiconductor layer that meet a p-type _{Al x In y Ga 1 -x- y} N, p -type impurity may be Mg. For example, the second conductivity type semiconductor layer 904 may be p-type AlGaN / GaN.

As shown in FIG. 21A, the semiconductor laminate employed in this embodiment has a region where the first conductivity-type semiconductor layer 102 is exposed, and the first contact electrode 905 is disposed in the exposed region. Can be deployed. The second contact electrode 906 may be disposed on an upper surface of the second conductive semiconductor layer 904. The first and second contact electrodes 905 and 906 are not limited thereto, and may include Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, or the like, and may be provided in a single layer or It may be employed in a structure of two or more layers. For example, the first contact electrode 905 may include Cr / Au, and the second contact electrode 906 may include Ag.

The semiconductor light emitting device 910 may include an insulating layer 907 disposed on the light emitting stack. The insulating layer 907 may be SiO ₂ or SiN. The insulating layer 907 may have a first opening H1 connected to a partial region of the first contact electrode 905 and a second opening H2 connected to a partial region of the second contact electrode 906. . If necessary, the first and second openings H1 and H2 may be provided in plurality. The plurality of first and second openings H1 and H2 may be arranged along a predetermined interval.

First and second bonding electrodes BM1 and BM2 may be disposed on the insulating layer 907 so as to be separated from each other. The first bonding electrode BM1 may be electrically connected to the first contact electrode 905 through the first opening H1. The second bonding electrode BM2 may be electrically connected to the second contact electrode 906 through the second opening H2.

The bonding electrodes BM1 and BM2 include a first bonding metal layer 912 including a first reaction layer 912a and a second reaction layer 912b that may react with each other to form a eutectic metal. The reaction delay layer 915 is disposed between the first reaction layer 912a and the second reaction layer 912b.

The first reaction layer 912a is a layer connected to the light emitting stack, and may include at least one metal of Ni, Pt, Au, Cu, and Co. The second reaction layer 912b may include a metal or an alloy selected from the group consisting of Sn, In, Zn, Bi, Au, Co, and combinations thereof. The reaction delay layer 915 may include a metal or an alloy selected from the group consisting of Ti, W, Cr, Ta, and combinations thereof.

In addition, in the present embodiment, an antioxidant film 918 is disposed on the surface of the first bonding metal layer 912 as a cap layer, respectively. The antioxidant layer 918 may be a material having a lower oxidation reactivity than the material of the first reaction layer 912a provided on the surface thereof. For example, the antioxidant layer 918 may be selected from the group consisting of Pd, Pt, Ru, Rh, Ag, Os, Ir, Au, and combinations thereof. Preferably, the antioxidant layer 918 may be Pd, Pt, or a combination thereof.

Although not limited thereto, the antioxidant layer 918 may have a thickness for obtaining a sufficient effect without substantially hindering a reaction between the bonding metal layers. For example, the anti-oxidation film 918 may have a thickness in the range of 10 to 100 GPa.

Referring to FIG. 21B, a permanent substrate 921 may be provided as a package substrate of the semiconductor light emitting device 910. The permanent substrate 921 has first and second electrodes 926a and 926b, and the first and second electrodes 926a and 926b have second bonding metal layers similar to the first bonding metal layer 912, respectively. 922 may be disposed.

The second junction metal layer 922 includes a first reaction layer 922a, a reaction delay layer 925, and a second reaction layer 922b that are sequentially disposed on the first and second electrode structures 926a and 926b. ), An anti-oxidation film 928 may be included. Each layer may be formed of a material similar to the corresponding element of the first bonding metal layer. In the present embodiment, the second bonding metal layer 922 is illustrated as having a structure corresponding to the first bonding metal layer, but may be formed to have different layers. For example, one of the first and second bonding metal layers 922 may not include a reaction delay layer or an antioxidant layer. In addition, the material of the corresponding layer can also be formed from other materials.

Next, as shown in FIG. 21C, the semiconductor light emitting device 910 is disposed on the permanent substrate 921 such that the first and second junction metal layers 912 and 922 face each other, and heat is applied to the first substrate. And the second bonding metal layers 912 and 922 are melted to form a desired eutectic metal bonding layer EM.

By suppressing generation of oxide films on the surfaces of the first and second bonding metal layers 912 and 922 before or during the connection, an advantageous bonding interface state can be obtained to obtain bonding strength. In addition, the reaction delay layers 915 and 925 may delay the reaction between the first reaction layers 912a and 922a and the second reaction layers 912b and 922b to ensure a high filling rate over the entire junction region.

Next, as shown in FIG. 21D, the growth substrate 901 may be separated from the first conductivity-type semiconductor layer 902. This separation process may be performed by irradiating a laser to the interface between the growth substrate 901 and the first conductivity-type semiconductor layer 902. If necessary, a wavelength converting part such as a phosphor layer or an optical lens may be further formed on the opposite side of the permanent substrate 921.

In the above-described embodiment, only one semiconductor light emitting device is illustrated, but this is for convenience of description, and may be implemented in a process of bonding a wafer in which a plurality of semiconductor light emitting devices are implemented with a corresponding permanent substrate. In addition, the semiconductor light emitting devices may be implemented by mounting a plurality of semiconductor light emitting devices separated by individual chip units on a permanent substrate.

Hereinafter, the operation and effects of the antioxidant film employed in the present invention will be described with reference to the following examples.

< Example 3 >

On the epitaxial layer (wafer level) for the GaN light emitting device, a Ni layer of 8000 Å thick and a Sn layer (first junction metal layer) 11000 Å thick, respectively, were formed as first and second reaction layers. Here, a Ti layer having a thickness of 1000 mm was further introduced as an adhesive layer between the Ni layer and the epitaxial layer. As the first and second reaction layers, a Ni layer 6000 m thick and a Sn layer (second junction metal layer) 8000 m thick were formed on the silicon substrate.

A Pt film was introduced as an anti-oxidation film on the surfaces of the first and second bonding metal layers, i.e., the Sn layer on both sides, but the thicknesses (15 kV, 30 kPa, 50 kPa) were varied for each sample.

Subsequently, heat was applied so that the GaN light emitting element and the silicon substrate were joined by the first and second bonding metal layers to form a eutectic metal bonding layer.

< Example 4 >

In this embodiment, the reaction delay layer was applied together with the antioxidant film to check the effect thereof.

An 8000 Å thick Ni layer (first junction metal layer) was formed on the epitaxial layer (wafer level) for the GaN light emitting device. Here, a Ti layer having a thickness of 1000 mm was further introduced as an adhesive layer between the Ni layer and the epitaxial layer. As the first and second reaction layers, a Ni layer of 6000 m thick and a Sn layer (second junction metal layer) of 19000 m thick were formed on the silicon substrate.

A Pd film was introduced as an anti-oxidation film on the surfaces of the first and second bonding metal layers, that is, the Ni layer surface and the Sn layer surface, respectively, but the thicknesses (15Å, 25Å, 50Å) were varied for each sample. In addition, the second bonding metal layer additionally introduced a Ti layer as a reaction delay layer between the Ni layer and the Sn layer, but the thickness of each sample (100 μs, 200 μs) was varied.

Subsequently, heat was applied so that the GaN light emitting element and the silicon substrate were joined by the first and second bonding metal layers to form a eutectic metal bonding layer.

After completing the bonding process of the samples obtained in Examples 3 and 4, the bonded state of each sample was evaluated by visual observation and SAM analysis. The results of each individual sample were evaluated as "very good", "good" and "bad" according to the occurrence area of the bonding defects, and are shown in Tables 1 and 2 below.

Sample of Example 3 3A 3B 3C Pt thickness 15 30 50 Joining State Evaluation Good Very good Very good

Sample of Example 4 4A-1 4B-1 4C-1 4A-2 4B-2 4C-2 Pd thickness 15 25 50 15 25 50 Ti thickness 100 100 100 200 200 200 Joining State Evaluation Good Good Very good Good Good Very good

As a result of the present embodiment, it can be seen that the bonding state is significantly improved by the introduction of the antioxidant film, the effect is somewhat different depending on the thickness, but when implemented in a thickness of generally 10Å or more, preferably 30Å or more, the antioxidant effect It was confirmed that the improvement effect by.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations can be made without departing from the technical spirit of the present invention described in the claims. It will be obvious to those of ordinary skill in the field.

Claims (10)

Forming first and second bonding metal layers on one surface of the first and second bonding objects, respectively;
Disposing the second bonding object on the first bonding object such that the first bonding metal layer and the second bonding metal layer face each other; And
Reacting the first and second bonding metal layers to form a eutectic metal bonding layer,
At least one of the first bonding metal layer and the second bonding metal layer,
A first reaction layer disposed on at least one surface of the first and second bonding objects and having a first metal;
A second reaction layer disposed on the first reaction layer and having a second metal reacting with the first metal to provide a eutectic metal;
A metal or alloy disposed between the first reaction layer and the second reaction layer to delay a reaction between the first metal and the second metal and selected from the group consisting of Ti, W, Cr, Ta and combinations thereof. A reaction delay layer having
At least one of the first junction metal layer and the second junction metal layer has an anti-oxidation film formed on an upper surface thereof, wherein the anti-oxidation film is formed of a metal junction layer formed of a metal or an alloy having a lower oxidation reactivity than the junction metal layer located thereunder. Way.
The method of claim 1,
And the anti-oxidation film is disposed on upper surfaces of the first and second bonding metal layers, respectively.
The method of claim 2,
The anti-oxidation film is a material different from the material of the corresponding junction metal layer located below and includes a metal or alloy selected from the group consisting of Pd, Pt, Ru, Rh, Ag, Os, Ir, Au, and combinations thereof.
The junction metal layer located below the antioxidant layer comprises a metal or alloy selected from the group consisting of Sn, In, Zn, Bi, Pb, Ni, Au, Pt, Cu, Co and combinations thereof.
The method of claim 3,
The antioxidant film is a metal bonding layer forming method having a thickness of 10 두께 to 100Å.
delete delete The method of claim 1,
The first reaction layer comprises at least one metal of Ni, Pt, Au, Cu and Co,
And the second reaction layer comprises a metal or an alloy selected from the group consisting of Sn, In, Zn, Bi, Au, Co and combinations thereof.
delete Providing a light emitting stack in which a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer are sequentially formed on a substrate for semiconductor growth;
Forming a first bonding metal layer on the light emitting laminate, and forming a second bonding metal layer on the permanent substrate;
Disposing the light emitting stack on the permanent substrate such that the first bonding metal layer and the second bonding metal layer contact each other;
Reacting the first bonding metal layer with the second bonding metal layer to form a eutectic metal bonding layer such that the light emitting laminate and the permanent substrate are bonded to each other; And
Removing the semiconductor growth substrate from the light emitting laminate;
At least one of the first bonding metal layer and the second bonding metal layer,
A first reaction layer disposed on at least one surface of the first and second bonding objects and having a first metal;
A second reaction layer disposed on the first reaction layer and having a second metal reacting with the first metal to provide a eutectic metal;
A metal or alloy disposed between the first reaction layer and the second reaction layer to delay a reaction between the first metal and the second metal and selected from the group consisting of Ti, W, Cr, Ta and combinations thereof. A reaction delay layer having
At least one of the first junction metal layer and the second junction metal layer includes an anti-oxidation film formed on an upper surface thereof, wherein the anti-oxidation film is formed of a metal or an alloy having a lower oxidation reactivity than the corresponding junction metal layer disposed below. Way. delete

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