TWI531087B - Light emitting diode structure - Google Patents

Description

Light-emitting diode structure

This invention relates to a semiconductor structure, and more particularly to a light emitting diode structure.

The technology of bonding a Light Emitting Diode (LED) wafer to a lead frame has been developed for many years. According to the different solid crystal materials, it can be roughly divided into two types: the first one is a polymer conductive adhesive, and The second type is a metal welding material.

In the case of polymer conductive adhesives, since the colloidal material is used as the solid crystal bonding material of the light-emitting diode wafer, the heat resistance and thermal conductivity of the gel material are not good and the joint strength is insufficient, so that the high temperature or high current is high. Operating in an environment, it is brittle and the lifetime of the LED chip is reduced.

In the case of metal solder materials, it is mainly through a eutectic bonding technique for the solid crystal process. Since the operating temperature of the metal soldering material belongs to a high temperature, that is, between 280 ° C and 320 ° C, the problem that the light emitting diode wafer is susceptible to thermal stress residual or thermal stress concentration during the solid crystal is formed, thereby affecting the subsequent products. Structural reliability. Furthermore, the cost of the metal solder material is high and when applied to a plastic substrate, It is easy to cause yellowing of the plastic substrate and cause light absorption.

The invention provides a light emitting diode structure which has better structural reliability.

The light emitting diode structure of the present invention comprises a substrate, a metal material layer, a first metal film layer, a second metal film layer and a light emitting diode chip. The metal material layer is disposed on the substrate and has a first layer region, a second layer region, and a third layer region. The second layer region is located between the first layer region and the third layer region, wherein the melting point of the second layer region is higher than 110 ° C and lower than 280 ° C, and the melting point of the first layer region and the melting point of the third layer region are higher than 350 ° C. The first metal thin film layer is disposed on the first layer region of the metal material layer. The second metal thin film layer is disposed on the substrate and located between the substrate and the third layer region of the metal material layer. The light emitting diode chip is disposed on the first metal thin film layer, wherein the first metal thin film layer is located between the light emitting diode wafer and the first layer region of the metal material layer.

In an embodiment of the invention, the material of the first metal thin film layer and the material of the second metal thin film layer include silver, gold, nickel or copper.

In an embodiment of the invention, the first layer region of the metal material layer is a first intermetallic layer region, and the third layer region of the metal material layer is a second intermetallic layer region. The material of the first dielectric layer region and the material of the second dielectric layer region include gold iridium, silver tin, nickel iridium, nickel tin or copper tin.

In an embodiment of the invention, the second layer region of the metal material layer The material includes at least one alloy layer region, and the material of the second layer region includes tin antimony, tin antimony silver, tin antimony silver copper or tin antimony silver crucible.

In an embodiment of the invention, the second layer region of the metal material layer is a metal laminate region, wherein at least one germanium layer is present.

In an embodiment of the invention, the second layer region of the metal material layer is a metal laminate region in which at least one tin layer is present.

In an embodiment of the invention, the substrate comprises a lead frame, a printed circuit board, a ceramic substrate, a plastic substrate, an alumina substrate or an aluminum nitride substrate.

In an embodiment of the invention, the metal material layer has a thickness of between 0.5 micrometers and 5 micrometers.

In an embodiment of the invention, the thickness of the first metal thin film layer and the thickness of the second metal thin film layer are between 0.3 micrometers and 3 micrometers.

In an embodiment of the invention, the light emitting diode chip is a horizontal light emitting diode chip, a vertical light emitting diode chip or a flip chip light emitting diode chip.

Based on the above, since the melting point of the second layer region in the metal material layer of the present invention is higher than 110 ° C and lower than 280 ° C, it is lower than the conventional solid crystal melting point (280 ° C to 320 ° C) of the metal solder material. Therefore, the light-emitting diode structure of the present invention is less prone to thermal stress residual or thermal stress concentration during the die bonding process, and can have better structural reliability. Furthermore, since the metal material layer, the first metal thin film layer and the second metal thin film layer between the light-emitting diode wafer and the substrate are all made of a metal material, the light-emitting diode structure of the present invention can have better heat dissipation. And thermal conductivity. this In addition, the first layer region and the third layer region in the metal material layer of the present invention can increase the adhesion of the metal material layer to the first metal film layer and the second metal film layer, so that the light emitting diode structure has better structure. Structural reliability, and since the melting points of the first layer region and the third layer region in the metal material layer of the present invention are higher than 350 ° C, even if the light emitting diode structure of the present invention is used at a high temperature (greater than 90 degrees C) In the environment, the metal material layer does not appear to soften and affect the alignment accuracy of the substrate and the LED wafer.

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧Lighting diode structure

110‧‧‧Substrate

120‧‧‧Metal material layer

122‧‧‧First floor

124‧‧‧Second floor

126‧‧‧ third floor

130‧‧‧First metal film layer

140‧‧‧Second metal film layer

150‧‧‧Light Diode Wafer

D1, D2, D3‧‧‧ thickness

1 is a cross-sectional view showing a structure of a light emitting diode according to an embodiment of the present invention.

1 is a cross-sectional view showing a structure of a light emitting diode according to an embodiment of the present invention. Referring to FIG. 1 , in the embodiment, the LED structure 100 includes a substrate 110 , a metal material layer 120 , a first metal film layer 130 , a second metal film layer 140 , and a light emitting diode chip . 150.

In detail, the metal material layer 120 is disposed on the substrate 110 and has a first layer region 122, a second layer region 124, and a third layer region 126. The second layer region 124 is located between the first layer region 122 and the third layer region 126, in particular, the second layer region The melting point of 124 is higher than 110 ° C and lower than 280 ° C, and the melting point of the first layer region 122 and the melting point of the third layer region 126 are higher than 350 ° C. The first metal thin film layer 130 is disposed on the first layer region 122 of the metal material layer 120. The second metal thin film layer 140 is disposed on the substrate 110 and located between the substrate 110 and the third layer region 126 of the metal material layer 120. The light emitting diode chip 150 is disposed on the first metal thin film layer 130, wherein the first metal thin film layer 130 is located between the light emitting diode wafer 150 and the first layer region 122 of the metal material layer 120.

In the present embodiment, the substrate 110 is, for example, a lead frame, a printed circuit board, a ceramic substrate, a plastic substrate, an alumina substrate, or an aluminum nitride substrate. The first metal thin film 130 may be plated on the surface of the light emitting diode wafer 150 by plating, sputtering, or evaporation. Here, the material of the first metal thin film layer 130 includes silver, gold, nickel, copper or a combination thereof, and the thickness D2 of the first metal thin film layer 130 is, for example, between 0.3 μm and 3 μm. The second metal film 140 may be plated on the surface of the substrate 110 by plating, sputtering, or evaporation. Here, the material of the second metal thin film layer 140 includes silver, gold, nickel, copper or a combination thereof, and the thickness D3 of the second metal thin film layer 140 is, for example, between 0.3 μm and 3 μm.

In particular, the second layer region 124 of the metal material layer 120 of the present embodiment is a metal lamination region or an alloy layer region, wherein the material of the second layer region 124 is, for example, tin antimony, tin antimony silver, tin antimony silver copper. Or tin enamel silver enamel. For example, the second layer region 124 may be a layer of tin-bismuth alloy, or a laminated structure of a tantalum layer and a tin-bismuth alloy, or a two-layer metal comprising a tin layer and a tantalum layer. Stack layer structure. Wherein, if the second layer region 124 is a metal layered layer structure in which a tin layer and a tantalum layer are laminated, The thickness of each of the metal layers in the metal stack is substantially the same. The first layer region 122 of the metal material layer 120 of the present embodiment is a first intermetallic layer region, and the third layer region 126 of the metal material layer 120 is a second intermetallic layer region, wherein the first intermetallic layer region The material of the material and the second metal layer region includes gold bismuth, silver tin, nickel bismuth, nickel tin or copper tin or a combination thereof. Here, the thickness D1 of the metal material layer 120 is between 0.5 μm and 5 μm. In addition, the LED chip 150 of the present embodiment is a horizontal LED chip, a vertical LED chip, or a flip-chip LED chip, which is not limited herein.

More specifically, the metal material layer 120 is formed of a layer of a solid crystal material having the same material and characteristics as the second layer region 124. The step of forming the metal material layer 120 is as follows. First, a layer of a solid crystal material is formed on the first metal thin film layer 130 or the second metal thin film layer 140 by plating, evaporation, or sputtering. Then, the solid crystal material layer is heated at a first reaction temperature for a reaction time, and a first intermetallic layer region and a second portion are formed between the first metal thin film layer 130, the solid crystal material layer and the second metal thin film layer 140, respectively. Intermetallic layer area. Wherein, the first reaction temperature is, for example, higher than 110 ° C and lower than 280 ° C, and the reaction time is, for example, 60 seconds to 120 seconds, and the heating may be performed by reflow furnace heating, laser heating or infrared heating. The above steps are a pre-fixing process, and the purpose is to form a first dielectric layer region and a second dielectric layer region, and the positional relationship between the LED wafer 150 and the substrate 110 can be preliminarily fixed in advance. Conducive to the subsequent process. Furthermore, since the pre-solid reaction time is short, the light-emitting diode wafer 150 does not cause thermal stress concentration or thermal stress residual. Thereafter, the layer of the solid crystal material is heated at a second reaction temperature, The first dielectric layer region and the second dielectric layer region are cured for a time to form a metal material layer 120 having a first layer region 122, a second layer region 124, and a third layer region 126. Wherein, the second reaction temperature is, for example, 80 ° C to 120 ° C, and the curing time is 30 minutes to 3 hours, and the heating may be performed by oven heating, hot plate heating or infrared heating. The purpose of the above steps is to allow the metal element or alloying element of the layer of the solid crystal material to diffuse with the elements of the first metal thin film layer 130 and the second metal thin film layer 140. That is, the first layer region 122 and the third layer region 126 of the metal material layer 120 change with the material composition of the first metal film layer 130 and the second metal film layer 140. Therefore, the materials of the first metal film layer 130 and the second metal film layer 140 may be the same or different, and the materials of the first layer region 122 and the third layer region 126 may be the same or different.

The first layer region 122 and the third layer region 126 formed after being heated by the second reaction temperature can increase the adhesion between the metal material layer and the first metal film layer and the second metal film layer, so that the structure of the light emitting diode is relatively The structural reliability is good, and since the melting points of the first layer region 122 and the third layer region 126 of the metal material layer 120 are higher than 350 ° C, the subsequent light emitting diode structure 100 is used in a high temperature (for example, greater than 90 ° C) environment. When the metal material layer 120 is not softened, the alignment relationship between the substrate 110 and the LED wafer 150 can be maintained, so that the LED structure 100 has better light extraction efficiency. Furthermore, the melting point of the second layer region 124 in the metal material layer 120 is higher than 110 ° C and lower than 280 ° C, which is lower than the conventional solid crystal melting point (280 ° C to 320 ° C) of the metal solder material. The light-emitting diode structure 100 of the embodiment is less prone to thermal stress residual or thermal stress concentration, and may have better structural reliability. In addition, due to the metal between the light emitting diode wafer 150 and the substrate 110 The material layer 120, the first metal film layer 130, and the second metal film layer 140 are all made of a metal material. Therefore, the light emitting diode structure 100 of the embodiment can have better heat dissipation and heat conduction effects.

In summary, since the melting point of the second layer region in the metal material layer of the present invention is higher than 110 ° C and lower than 280 ° C, the solid crystal melting point (280 ° C to 320 ° C) of the metal welding material is conventionally used. Therefore, the light-emitting diode structure of the present invention is less prone to thermal stress residual or thermal stress concentration, and can have better structural reliability. Furthermore, since the metal material layer, the first metal thin film layer and the second metal thin film layer between the light-emitting diode wafer and the substrate are all made of a metal material, the light-emitting diode structure of the present invention can have better heat dissipation. And thermal conductivity. In addition, since the melting points of the first layer region and the third layer region in the metal material layer of the present invention are higher than 350 ° C, even if the light emitting diode structure of the present invention is used in an environment of high temperature (greater than 90 ° C), The metal material layer also does not appear to soften and affect the alignment accuracy of the substrate and the LED wafer.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Lighting diode structure

110‧‧‧Substrate

120‧‧‧Metal material layer

122‧‧‧First floor

124‧‧‧Second floor

126‧‧‧ third floor

130‧‧‧First metal film layer

140‧‧‧Second metal film layer

150‧‧‧Light Diode Wafer

D1, D2, D3‧‧‧ thickness

Claims (19)

A light-emitting diode structure includes: a substrate; a metal material layer disposed on the substrate, and having a first layer region, a second layer region, and a third layer region, wherein the second layer region is located Between the first layer region and the third layer region, wherein the melting point of the second layer region is higher than 110 ° C and lower than 280 ° C, and the melting point of the first layer region and the melting point of the third layer region are higher than 350 a first metal thin film layer disposed on the first layer region of the metal material layer; a second metal thin film layer disposed on the substrate and located on the substrate and the third layer of the metal material layer And a light emitting diode chip disposed on the first metal thin film layer, wherein the first metal thin film layer is located between the light emitting diode wafer and the first layer region of the metal material layer. The light emitting diode structure according to claim 1, wherein the material of the first metal thin film layer and the material of the second metal thin film layer comprise silver, gold, nickel or copper. The light emitting diode structure according to claim 1, wherein the first layer region of the metal material layer is a first metal layer region, and the third layer region of the metal material layer is a first layer The material of the first intervening layer region and the material of the second interposer region include gold iridium, silver tin, nickel lanthanum, nickel tin or copper tin. The light emitting diode structure of claim 1, wherein the second layer region of the metal material layer comprises at least one alloy layer region, and the material of the second layer region The quality includes tin bismuth, tin bismuth silver, tin bismuth silver copper or tin bismuth silver enamel. The light emitting diode structure of claim 1, wherein the second layer region of the metal material layer is a metal laminate region, wherein at least one germanium layer is present. The light emitting diode structure of claim 5, wherein the second layer region of the metal material layer is a metal laminate region, wherein at least one tin layer is present. The light emitting diode structure according to claim 1, wherein the substrate comprises a lead frame, a printed circuit board, a ceramic substrate, a plastic substrate, an alumina substrate or an aluminum nitride substrate. The light-emitting diode structure of claim 1, wherein the metal material layer has a thickness of between 0.5 micrometers and 5 micrometers. The light emitting diode structure of claim 1, wherein the thickness of the first metal thin film layer and the thickness of the second metal thin film layer are between 0.3 micrometers and 3 micrometers. The light emitting diode structure of claim 1, wherein the light emitting diode chip is a horizontal light emitting diode chip, a vertical light emitting diode chip or a flip chip light emitting diode. Wafer. A light-emitting diode structure includes: a substrate; a metal material layer disposed on the substrate, and having a first layer region, a second layer region, and a third layer region, wherein the second layer region is located Between the first layer region and the third layer region, wherein the melting point of the second layer region is higher than 110 ° C and lower than 280 ° C, and the melting point of the first layer region and the melting point of the third layer region are higher than 350 °C, the layer of metal material The first layer region is a first metal layer region, and the third layer region of the metal material layer is a second metal layer region; a first metal film layer is disposed on the first layer of the metal material layer a second metal film layer disposed on the substrate between the substrate and the third layer region of the metal material layer; and a light emitting diode chip disposed on the first metal film And a layer of the first metal thin film between the light emitting diode wafer and the first layer region of the metal material layer. The light emitting diode structure according to claim 11, wherein the material of the first metal thin film layer and the material of the second metal thin film layer comprise silver, gold, nickel or copper. The illuminating diode structure of claim 11, wherein the second layer region of the metal material layer comprises at least one alloy layer region, and the material of the second layer region comprises tin bismuth, tin antimony silver, Tin bismuth silver or tin bismuth silver enamel. The light-emitting diode structure of claim 11, wherein the second layer region of the metal material layer is a metal laminate region, wherein at least one germanium layer is present. The light-emitting diode structure of claim 14, wherein the second layer region of the metal material layer is a metal laminate region, wherein at least one tin layer is present. The light emitting diode structure according to claim 11, wherein the substrate comprises a lead frame, a printed circuit board, a ceramic substrate, a plastic substrate, an alumina substrate or an aluminum nitride substrate. The light emitting diode structure according to claim 11, wherein the The thickness of the layer of metallic material is between 0.5 microns and 5 microns. The light emitting diode structure of claim 11, wherein the thickness of the first metal thin film layer and the thickness of the second metal thin film layer are between 0.3 micrometers and 3 micrometers. The light emitting diode structure of claim 11, wherein the light emitting diode chip is a horizontal light emitting diode chip, a vertical light emitting diode chip or a flip chip light emitting diode. Wafer.