KR20140086373A - Wafer for led and manufacturing method thereof - Google Patents

Abstract

[Objective] Provided are a wafer for an LED, where a metal layer is uniformly and integrally formed therewith, since delamination between layers does not occur and contact thermal resistance with the LED is very small, a plating scheme of maintaining stable heat radiation and mechanical strength is applied thereto, and a problem of high-temperature heat is not caused on an opposite bottom surface due to high-temperature heat generated when semiconductor is conjugated thereon, and a method of manufacturing the same. [Solution] A complex low support layer having a sandwich shape is formed by forming Cu plating layers on both surface of a core material having Mo, wherein Ni plating layers of Ni or Ni alloy are formed on both surfaces of each of the Cu plating layers. In addition, upper and lower Au plating layers are formed on upper and lower surface of the complex low support layer. Connection plating layers are formed on the upper and lower Au plating layers by one of AuSn alloy, Au/Sn lamination and In. The lower connection plating layer is polished from the lower surface to expose the Au plating layer and the plating layer connected to an LED, on which the plating layer of AuSn alloy, Au/Sn lamination or In remains, is preserved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a wafer for LED,

The present invention relates to a wafer for an LED, which functions to hold an LED as a semiconductor device and prevent it from being stored in the wafer, and a method of manufacturing the same.

BACKGROUND ART [0002] Semiconductor devices such as LEDs (light emitting diodes) and semiconductor integrated circuits tend to increase the amount of heat radiation due to recent high density and high output, There is a tendency that fineness, delamination and accompanying corrosion resistance and impact resistance are required. In addition, with respect to high heat dissipation performance, it is also required to have an unmodified stability or a low thermal expansion coefficient necessary for maintaining contact with an LED or the like. Conventionally, a sapphire substrate has been used as the wafer for LED, but in recent years, thermal conductivity and impact resistance have been insufficient.

When the semiconductor element is an LED, the LED is mounted on the sapphire substrate. However, if the semiconductor element is mounted on the sapphire substrate, heat generated from the LED's light emitting portion is likely to accumulate between the sapphire substrate and the semiconductor element, In particular, the brightness of the LED is lowered, and damage such as destruction of the sapphire substrate occurs. Therefore, a metal heat-radiating substrate (wafer) having a good thermal conductivity and a low thermal contact resistance is used . For example, it is a metal called a metal wafer such as copper, molybdenum, tungsten, or titanium. It is known that molybdenum (Mo) is sandwiched mainly by plating of copper (Cu, Cu) (hereinafter referred to as "DMD"). However, these metals still have problems in terms of corrosion resistance, chemical resistance, thermal conductivity with LED, and the like.

Generally, properties and performance required for wafers are required to have excellent thermal conductivity. Therefore, it is required to have a low thermal contact resistance, a high stability without warpage and warpage, Mechanical strength and machinability are required. It is also required to be suitable for adhering or brazing to be adhered, and having excellent chemical resistance. These properties have conventionally been developed so as to comprehensively exhibit layer bonding of a plurality of metal materials (clad materials). As a means for taking up this multilayer structure, a rolling method and a hot uniaxial working method in which a clad material is pressed and joined are conventionally used. However, in the rolling method in particular, it was difficult to obtain the uniformity of the layer thickness.

In order to solve such a problem, the applicant of the present application has proposed a plating method in which a plating layer is symmetrically laminated on both upper and lower surfaces of a core material, both surfaces of which are relatively soft and can be turned into a reflective surface, And proposed this (Patent Document 1).

Japanese Patent Laid-Open Publication No. 2012-109288

(Summary of the Invention)

(Problems to be Solved by the Invention)

According to the conventional LED wafer, since the both surfaces are made of the Au plating layer, the elasticity and the reflectivity are obtained, and the bonding surface of the semiconductor becomes the protection surface. However, If the lower surface of the opposite side of the bonding surface has a high temperature, there is a problem that a problem occurs in the dicing step by plating and alloying with Ni or Cu of the wafer.

Further, as a result of various experiments, it has been found that even when the lower surface is an alloy plating layer of AuSn or the like, the state of the alloy itself changes due to the heat at the time of bonding, and in this case, a problem arises in use on the user side.

SUMMARY OF THE INVENTION In view of the above-described facts, the present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a metal layer which is uniformly and integrally formed and which does not cause delamination between layers and has a very low contact thermal resistance with LED, And an object of the present invention is to provide a wafer for an LED and a method of manufacturing the same that does not cause a problem due to high temperature on the opposite surface due to high heat generated when bonding with a semiconductor.

In order to solve the above problems, the first invention is characterized in that an Au plating layer is formed on both upper and lower sides of the core material so as to be vertically symmetric about a thin plate-like core material made of Mo, and a core material is interposed between the both Au plating layers At least one of AuSn alloy, Au / Sn laminate, and In is formed on the Au plating layer on the upper surface side to which the LED is adhered, And a lower surface of the Au plating layer on the lower surface side is an exposed surface.

The second invention is characterized in that a sandwich-like composite underlayer is formed on both upper and lower surfaces of a core material made of Mo and the Ni plating layer of Ni or Ni alloy is sandwiched between the upper and lower surfaces of the Cu plating layer on both sides, A Au plating layer is formed on the Au plating layer on the upper and lower sides of the Au plating layer and a connecting plating layer of AuSn alloy, Au / Sn laminate or In is formed on the upper and lower Au plating layers on the upper and lower Au plating layers, Wherein the Au plating layer is exposed and the Au plating layer on the upper face side is provided with a plating layer for connection with an LED in which an AuSn alloy, an Au / Sn laminate, and a plating layer of In are left, do.

According to the above configuration, not only the thermal conductivity between the layers is good, but also the so-called " DMD " which has Cu plating layers on and under the core material of Mo and sandwiches Mo with Cu (thermal conductivity 420 W / Since the AuSn alloy has good flexibility, reflectivity and wettability, Au / Sn laminate, and In, it is possible to directly bond the LEDs directly without using an adhesive agent, and the contact resistance of heat conduction is greatly reduced.

In this regard, if the upper surface is an AuSn alloy, an Au / Sn laminate, or a connection plated layer of In, there is no need to attach AuSn or the like by sputtering (dry plating) in a post process (customer side) In this respect, it brings advantages to customers.

In addition, when the Au plating layer is AuSn alloy, Au / Sn laminate, or In plating, there is an advantage that a high melting point is achieved. That is, when Au: Sn is 8: 2, the melting point is 280 占 폚, but when Au is mixed with Au in the lower layer, the melting point rises to 300 占 폚. In the case of In, the melting point is 156 占 폚 in the case of In, but it is mixed with Au in the lower layer and is raised to 300 占 폚 or more, thereby preventing redissolution in which attachment of the LED becomes unstable.

Further, unlike the case where the lower surface is plated with AuSn or the like, there is no such thing as a problem occurs in the process of the user because the high-temperature state is changed when the LED is bonded. That is, when the bottom surface is plated with AuSn or the like, it is melted at the time of joining of LED or the like to make the appearance uneven, or alloy with Au plating, which causes a problem in the dicing process. Further, when the alloy plating layer is formed, the alloy is continuously oxidized or alloyed.

When the one surface (bottom surface) is Au-plated in this manner, these problems can be prevented, which is advantageous to the user. In addition, the use of only the Au of the noble metal having this characteristic is advantageous in terms of cost. It is also advantageous in terms of cost to not use masking which requires labor.

Ni is a stable metal and has good compatibility with other plating bases and contributes to the formation of a Cu plating layer on the core material and the formation of an Au plating layer on the Cu plating layer and maintains a strong bonding of the Cu plating layer and the Au plating layer So that the characteristics of the Au plating layer are also easily exhibited. Although Ni has a thermal conductivity of 90 W / (m. K), the LED wafer can exhibit a high heat radiation performance as a whole by being thinly plated.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, since the metal layer is uniformly and integrally formed by the plating method, no peeling occurs between the layers and the contact thermal resistance with the LED is extremely small, And there is no problem caused by high temperature in the Au plating layer on the bottom surface even if the high temperature generated at the time of connection with the LED is lowered. Thus, there is an excellent effect that the user is greatly advantageous. Further, according to the manufacturing method, it is easy to form the Au plated layer on the upper surface and the connecting plating layer on the upper surface, which is advantageous for mass production.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional explanatory view schematically showing a layer structure of a wafer for LEDs according to a first embodiment of the present invention; FIG.
Fig. 2 is an explanatory view schematically showing the use state of the LED-use wafer. Fig.
Fig. 3 is a cross-sectional explanatory view schematically showing a layer structure of an LED wafer showing a second embodiment; Fig.
4 is a cross-sectional explanatory view schematically showing a layer structure of an LED wafer showing a third embodiment.

(Mode for carrying out the invention)

Since the present invention forms the layer structure by plating, the core material 1 of the thin metal plate is required as the base material. In this method, a thin plate material in which a metal of Mo is slimly thinned to about 50 to 200 mu m is used, and a plurality of LED wafers (P, P, ...) are mass-produced by subdividing the plating layers. Further, W can be used instead of Mo. However, it is generally relatively expensive.

The plating is preferably electrolytic, electroless, ion plating (IP) or the like, but is not particularly limited as long as it is a plating. In any case, by plating, the metal layers other than the connection plating layer are formed in a uniform layer having symmetrical upper and lower parts, and each layer is tightly bonded. Further, in addition to the Cu plating, the Cu ion plating method can be optimally used for forming the Cu plating layers 5, 5.

The plated thicknesses of the Ni plated layers 3 and 7, the Cu plated layer 5 and the Au plated layers 9 and 11 as well as the core material 1 are the same as the thicknesses of the wafers P The right side of each embodiment is shown in the proper range. For example, in Fig. 1, the Cu plating layers 5 and 5 have a display range of 3.0 to 20.0 m.

(Example 1)

Figs. 1 and 2 show one embodiment. First, Cu plating layers 5 and 5 are formed on both surfaces of a core material 1 made of a metal plate of Mo with thin first Ni plating layers 3 and 3 therebetween . The structure having the Cu plating layers 5 and 5 on both surfaces of the core material 1 is referred to as " DMD " in this specification. Further, Au plating layers 9 and 11 are formed on both Cu plating layers 5 and 5 with Ni plating layers 7 and 7 therebetween. In the drawing, reference numeral 2 denotes a composite underlayer having a sandwich structure in which both surfaces of a Cu plating layer 5 are sandwiched by Ni plating layers 3 and 7.

Conventionally, since the plating method is not used, it is difficult to cut and adjust the material to, for example, about 1 mu m, and peeling easily occurs between the materials. In this case, it is possible to form a uniform thickness by plating . 2, the Cu plating layer 5 is formed on the core material 1, and the Au plating layers 9 and 11 are formed on the Cu plating layer 5 with the Ni plating layers 3 and 7, respectively, The bonding strength between the layers is extremely strong and no peeling occurs. Therefore, heat dissipation is stably maintained and adhesion of the LED 10 is stably maintained.

2 schematically shows a state in which the LED 10 is mounted on the package 16 with the wafer W for LED interposed therebetween. The package 16 is attached by an adhesive. Further, Ag or AuSn alloy paste can be effectively used for the adhesive. However, in the LED 10, the connection plating layer 13 of AuSn is used instead of the adhesive, and is directly bonded thereto. This gives the customer a cost advantage.

In addition, when the semiconductor element is an LED in particular, light or radiant heat is reflected by the respective plating layers 13, 14 and 15 of the AuSn alloy, Au / Sn laminate and In, The luminous efficiency is increased.

In the case of the present invention, each of the connecting plated layers 13 on the upper surface is a plated layer of AuSn alloy, while the lower surface is characterized by being an Au plated layer 11 of a single metal. With respect to this point, if plating such as AuSn is applied to the side (lower surface) rather than the bonding surface, the appearance becomes uneven or is alloyed with the Au plating of the DMD to cause a trouble in the dicing step However, since the lower surface is the Au plating layer 11, this problem can be prevented as described above.

Next, Examples 2 and 3 are referred to, which have the same characteristics as those described above.

(Example 2)

As shown in Fig. 3, the LED wafer P is formed by forming Cu plating layers 5 and 5 on both sides of a core material 1 made of a metal plate of Mo with first Ni plating layers 3 and 3 therebetween Au plating layers 9 and 11 are formed on the both Cu plating layers 5 and 5 with the second Ni plating layers 7 and 7 interposed therebetween to form the Cu plating layer 5 on the surface of the nickel plating layer 7, (3, 7) are sandwiched between them.

The connection plating layer 14 is the Au / Sn laminated plating 14, and both layers are combined to exhibit adjustable flexibility and reflectivity. Unlike the above embodiment, since it is binary alloy plating, it is difficult to maintain the balance of the alloy ratio of Au and Sn, and the plating solution is also unstable, so that the solution tends to be unbalanced. Therefore, the plating solution is frequently replaced, and the operation cost tends to be increased, so that the above embodiment is advantageous.

(Example 3)

4, Cu plating layers 5 and 5 are formed on both surfaces of the core material 1 with the first Ni plating layers 3 and 3 interposed therebetween. Au plating layers 9 and 11 are sequentially formed with the second Ni plating layers 7 and 7 in between and an In plating layer 15 is formed as a connection plating layer on the Au plating layer 9 on the upper side, Au plating layer 11 is present.

P Wafer for LED 1 Core
2 composite underlayer 3 Ni plated layer
5 Cu plating layer 7 Ni plating layer
9 Au plating layer 11 Au plating layer
13 Connection layer of AuSn alloy 14 Connection plating layer of Au / Sn laminate
The connection plated layer of 15 In

Claims (3)

An Au plating layer is formed on the upper and lower surfaces of the core material so as to be vertically symmetrical with respect to the core of the thin plate made of Mo and a core layer made of a composite material of at least a Cu plating layer And a connection plating layer of AuSn alloy, Au / Sn laminate or In is formed on the Au plating layer on the upper surface side to which the LED is adhered, and the lower surface of the Au plating layer on the lower surface side is exposed Wherein the wafer is a silicon wafer. The composite ground layer according to claim 1, wherein the composite underlayer is a sandwich structure having a thin Ni or Ni alloy plating layer on both upper and lower surfaces of a Cu plating layer, the Cu plating layer being formed on the upper and lower sides of the core material with the Ni plating layer serving as the ground, And the Au plating layer is formed on each of the upper and lower composite undercoat layers with the Ni plating layer serving as a base. A sandwich-type composite underlayer in which Ni plating or Ni alloy plating is sandwiched between the upper and lower surfaces of the Cu plating layer on both upper and lower surfaces of the core made of Mo and an Au plating layer is formed on the upper and lower surfaces of the composite underlayer And a connection plating layer of AuSn alloy, Au / Sn laminate or In is formed on the upper and lower surfaces of the Au plating layers on the upper and lower sides of the Au plating layer, and the connection plating layer is cut in the lower Au plating layer, Wherein the Au plating layer on the upper face side is provided with a plating layer for connection with an LED in which a AuSn alloy, an Au / Sn laminate, and a plating layer of In are left.

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