CN104241496A - Metal substrate for LED - Google Patents

Abstract

The present invention provides a metal substrate for LEDs. As the core material of the metal substrate, other metals with characteristics close to those of Mo (materials with high temperature resistance, small thermal expansion coefficient, and extremely stable in vacuum) are focused on. It has been improved to have high luminance and high heat dissipation functions, and it is possible to reliably bond and install LED elements without failure even if you are unskilled. The adjustment coating for improving the hardness of CuW is formed on the core substrate of the CuW alloy through the base coating of Ni or Ni-P alloy, and the adjustment coating is any one of the following three adjustment coatings: the alloy adjustment coating of AuSn ( 3); Au and Sn laminated composite adjustment coating (4); In and Au laminated composite adjustment coating (5), through which the adjustment coating can be bonded to the epitaxial layer of the LED element.

Description

Metal Substrates for LEDs

technical field

The present invention relates to a metal substrate for LEDs which is also called a metal wafer by cutting out and using mounted LED elements similarly to a silicon wafer or the like.

Background technique

Hitherto, the applicants of the present application have conducted research and development of plating methods targeting substrates for LEDs characterized by high luminance and high heat dissipation, and manufactured and provided Cu-plated substrates on both sides of a Mo core material. Metal substrate (Patent Document 1). This metal substrate is referred to as "DMD" in this specification.

DMD is currently used a lot and is provided to manufacturers. At the follow-up manufacturers, LED components are assembled through the delicate process of bonding, and finally assembled into LED chips. This bonding process is not handy.

Patent Document 1: JP Unexamined Publication No. 2012-109288

The reason for this is that in the case of DMD, since the core material Mo as its base material is flexible, warpage occurs during the bonding process, so that unbonded parts and the like occur, causing problems in bonding. For this reason, a large number of experiments have been carried out, and it has been tried to improve the DMD by applying a plating layer, but it has become a method of applying a plating layer on top of the instability of the flexibility of Mo (or DMD) (see Table 1), so it cannot be achieved. Solve this shortcoming fundamentally.

[Table 1]

DMD CuW(11%Cu) hardness 160 300 Thermal conductivity (W/(m k)) 160～180 170～180 Coefficient of thermal expansion (10 ⁶ /k) 5.1～(Adjusted by Cu thickness) 6.5

Contents of the invention

In view of the above circumstances, the object of the present invention is to provide a metal substrate for LEDs. As the core material of the metal substrate, the material has a material close to that of Mo (a material that is resistant to high temperatures, has a small thermal expansion coefficient, and is extremely stable in a vacuum). Other metals with different characteristics can have high brightness and high heat dissipation functions by improving them, and LED components can be reliably bonded and installed without failure even if they are unskilled.

In order to solve the above-mentioned problems, the present invention provides a metal substrate for LEDs, which is characterized in that an adjustment plating layer for improving the hardness of CuW is formed on a core substrate of CuW alloy via a base plating layer of Ni or Ni-P alloy, The adjustment coating is any one of the following three adjustment coatings:

(1) AuSn alloy adjustment coating 3;

(2) Composite adjustment coating 4 laminated with Au and Sn;

(3) Composite adjustment coating layer 5 laminated with In and Au,

The adjustment plating layer can be adhered to the epitaxial layer of the LED element.

Since the metal substrate for LED is constituted as above, the central core substrate (core material) is an alloy of Cu and W (CuW, 5 to 20% of Cu (the remainder is W)). This CuW alloy material is produced by dipping a Cu plate into a W sintered body. In addition, no adhesive is added directly, but it is possible to adhere to the epitaxial layer 7 of the LED element through the adjustment plating layers 3 , 4 , and 5 .

In addition, the core substrate 1 is CuW, which is brittle but has hardness (see Table 1). Therefore, it is a material that is difficult to warp in the epitaxial bonding process, and the adjustment plating layers 3, 4, and 5 can be stably held at their positions without deformation. superior. Furthermore, the adjustment plating layers 3 , 4 , and 5 are soft and suitable for adjustment, thereby reducing the hardness of CuW to a level suitable for bonding LED elements. In addition, it has high brightness and high heat dissipation metal properties, and is suitable for mounting LED components.

As mentioned above, according to the present invention, the metal substrate for the LED uses CuW, which is high temperature resistant, has a small thermal expansion coefficient, and is extremely stable in vacuum, as a core substrate, and has a hardness-adjusting plating layer of CuW formed on at least one side thereof, thereby improving its performance. The material of CuW, which has high hardness and no flexibility in shape, is easy to epitaxially bond LED elements without error, so LED elements can be properly mounted without skill, and can effectively exert the characteristics of high brightness and high heat dissipation.

Description of drawings

FIG. 1 is an explanatory cross-sectional view showing an LED substrate according to an embodiment of the present invention in a used state.

FIG. 2 is an explanatory cross-sectional view showing a substrate of another embodiment.

Fig. 3 is an explanatory cross-sectional view showing a substrate of still another embodiment.

FIG. 4 is an explanatory cross-sectional view showing a substrate of still another embodiment.

Fig. 5 is a cross-sectional explanatory view showing a substrate of still another embodiment.

Fig. 6 is a cross-sectional explanatory view showing a substrate of still another embodiment.

Fig. 7 is a cross-sectional explanatory view showing a substrate of still another embodiment.

Fig. 8 is a cross-sectional explanatory view showing a substrate of still another embodiment.

Fig. 9 is a cross-sectional explanatory view showing a substrate of still another embodiment.

Detailed ways

In the present invention, the adjustment plating layers 3 , 4 , and 5 are layers that soften the hardness of “CuW” of the core substrate 1 and adjust it even if deformed, and there are the following three types.

(1) Adjustment coating of AuSn alloy 3

(2) Composite adjustment coating layered with Au and Sn 4

At this time, Au and Sn melt to become AuSn at the time of bonding.

(3) Composite adjustment coating layered with In and Au 5

In this case, since the melting point of In is as low as 156.4° C., there is an advantage that the bonding temperature can be lowered.

In addition, in the case of (2) and (3), it is the composite plating layers 4 and 5 where the plating layers are stacked, so there are also cases where the high-brightness Au plating layer 10 is the outer surface (see Fig. 4, Fig. 5, Fig. 8, Fig. 9).

Regarding the use of the metal substrate P for LED, for the mounting of the LED element, its epitaxial layer 7 and the adjustment plating layers 3, 4, 5 are bonded via the adhesive 6, and as the adhesive 6, the adjustment plating layers 3, 4 An AuSn alloy can be suitably used, and Au can be suitably used for the Au and In laminated plating layer 5 .

Example 1

FIG. 1 shows an example. In the metal substrate P for the LED, the core substrate 1 uses an alloy of copper and tungsten, that is, CuW, as the core material, and Ni (or Ni-P alloy) base layers 2 and 2 are interposed on both sides thereof. On the other hand, the soft adjustment plating layers 3 and 3 that suppress the hardness are formed, thereby having a multilayer structure of AuSn alloy plating layers on both sides.

FIG. 1 shows the state of use. An LED element is mounted on the upper surface via an AuSn adhesive 6 , and the epitaxial layer 7 peeled off from the sapphire is bonded to the adjustment plating layer 3 . Also, on the lower surface, the package substrate 8 and the AuSn alloy adjustment plating layer 3 are bonded via the adhesive 6 in the same manner. In addition, the alloy ratio of AuSn is 80:20.

Example 2

FIG. 2 shows the "single-sided AuSn" type implemented only on the upper side. Au plating layers 9, 9 are formed on both sides of a CuW core substrate 1 with base layers 2, 2 interposed therebetween, and an AuSn alloy adjustment plating layer is formed on the upper surface. 3. In addition, an LED element is bonded thereon via an epitaxial layer, and an Au plating layer 9 is formed on the lower surface, where a package substrate (not shown) is bonded.

Example 3

Figure 3 shows the "double-sided AuSn" type, which is different from the embodiment of the above-mentioned Figure 2 of the similar example, the AuSn alloy coating is applied on the lower Au coating 9, and the upper and lower sides are AuSn alloy adjustment coatings 3, 3 overlapping with Au , and has a structure in which the hardness of CuW is further relaxed.

Example 4

Figure 4 is a "single-sided AuSn stacking" type, in which Au plating layers 9, 9 are formed on both sides of the core substrate 1, and on the upper part, a composite adjustment plating layer 4 is formed on the plating layer 9 with Au and Sn as the upper and lower plating layers. The surface is the Au plating layer 10 therein, and the above-mentioned Au plating layer 9 is exposed on the lower surface.

Example 5

FIG. 5 shows a similar example to FIG. 4 , in which Au and Sn are formed on the top and bottom of the Au coatings 9 and 9 to form composite adjustment coatings 4 and 4 stacked as upper and lower coatings, forming a vertically symmetrical multilayer structure.

Example 6

6 shows the "single-sided In" type, in which Au plating layers 9, 9 are formed on both sides of the core substrate 1, and a composite adjustment plating layer 5 formed by stacking In and Au plating layers is formed only on the upper side, and a single Au plating layer 9 is formed on the lower surface.

Example 7

Fig. 7 is a "double-sided In" type similar to Fig. 6, and composite adjustment coatings 5, 5 formed by stacking upper and lower coatings of In and Au are formed on the upper and lower surfaces, forming a vertically symmetrical multilayer structure.

Example 8

Figure 8 is a "single-sided In" type. Au plating layers 9, 9 are formed on both sides of the core substrate 1, and on the upper surface, a composite adjustment plating layer 5 formed by laminating the upper and lower plating layers of In and Au is formed. The outer surface is Au plating layer 10 as one side of the composite.

Example 9

Figure 9 is a "double-sided In" type similar to the situation in Figure 8. On the lower surface, a composite adjustment coating layer 5 formed by stacking the upper and lower coating layers of In and Au is also formed on the Au coating layer 9. In the multilayer structure, the two outer layers The surfaces are all composite Au plating layers 10, 10, which are formed with high brightness and high softness.

Symbol Description

Metal substrate for P LED

1 basal layer

3 AuSn alloy adjustment coating

4 Au and Sn laminated composite adjustment coating

5 Composite adjustment coating layered by In and Au

7 epitaxial layer

9 Au plating

10 Au coating in composite adjustment coating

Claims (3)

1. A metal substrate for LED, characterized in that, On the core substrate of the CuW alloy, an adjustment coating for improving the hardness of CuW is formed through a base coating of Ni or Ni-P alloy, and the adjustment coating is any one of the following three adjustment coatings: (1) AuSn alloy adjustment coating; (2) Composite adjustment coating layered with Au and Sn; (3) Composite adjustment coating layered with In and Au, The adjustment plating layer can be adhered to the epitaxial layer of the LED element. 2 . The metal substrate for LED according to claim 1 , wherein the mounting surface bonded to the epitaxial layer of the LED element is an Au plating layer in the composite adjustment plating layer. 3 . 3 . The metal substrate for LED according to claim 1 or 2 , characterized in that, under the composite adjustment coating layer is an Au coating layer. 4 .