Method for manufacturing a light-emitting device and a light-emitting device

Abstract

This invention provides a manufacturing method for a light-emitting device that achieves high mounting accuracy and strong bonding when mounting semiconductor light-emitting elements, and involves a short process. [Solution] A method for manufacturing a light-emitting device, comprising: a heating step of bringing a plurality of semiconductor light-emitting elements, each having an electrode portion containing a first metal, and a substrate having a plurality of connection terminal portions containing a first metal, to a first temperature; a temporary bonding step of aligning the electrode portions and the connection terminal portions while maintaining the first temperature, and then pressing the first metal of the electrode portions and the first metal of the connection terminal portions together with a first pressure to form an intermediate; and a final bonding step of applying a second pressure less than or equal to the first pressure between the plurality of semiconductor light-emitting elements and the substrate, bringing the intermediate to a second temperature, and then cooling, wherein either the electrode portions or the connection terminal portions further have a metal multilayer film containing a second metal and a third metal located between the first and second metals, the first temperature is lower than the solidus temperature of the second metal, and the second temperature is above the solidus temperature of the second metal and below the liquidus temperature.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a light-emitting device, and particularly to a method for manufacturing a light-emitting device using flip-chip mounting.

Background Art

[0002] With the miniaturization and high functionality of light-emitting devices including semiconductor light-emitting elements, the demand for high-density mounting of semiconductor light-emitting elements has been increasing. In particular, in the mounting of semiconductor light-emitting elements, instead of the bonding method by wire bonding, flip-chip mounting in which a semiconductor light-emitting element is mounted and bonded to a circuit board through a plurality of bump electrodes arranged on its surface is used (for example, see Patent Document 1).

[0003] In recent years, in this flip-chip mounting, with the increase in the density of mounting of semiconductor light-emitting elements, the distance between adjacent semiconductor light-emitting elements has become narrower, and with the miniaturization of semiconductor light-emitting elements, the distance between a plurality of bump electrodes has also become narrower. For this reason, high mounting accuracy is required. In addition, the driving of a semiconductor light-emitting element generates heat of the semiconductor light-emitting element, and the thermal stress applied to the joint portion between the semiconductor light-emitting element and the circuit board increases with the increase in the density of mounting of the semiconductor light-emitting element, so a strong and highly reliable joint is required (for example, see Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The manufacturing method using the wet plating method disclosed in Patent Document 2 provides a joint with high mounting accuracy and excellent bonding strength and connection reliability. However, since it requires patterning and plating equipment, it tends to require a lot of equipment and the process is lengthy, and there is a need to achieve lower mounting costs. [Means for solving the problem]

[0006] A method for manufacturing a light-emitting device, comprising: a heating step of bringing a plurality of semiconductor light-emitting elements, each having an electrode portion containing a first metal, and a substrate having a plurality of connection terminal portions containing the first metal, to a first temperature; a temporary bonding step of aligning the electrode portions and the connection terminal portions while maintaining the first temperature, and then pressing the first metal of the electrode portions and the first metal of the connection terminal portions together with a first pressure to form an intermediate; and a final bonding step of applying a second pressure less than or equal to the first pressure between the plurality of semiconductor light-emitting elements and the substrate, bringing the intermediate to a second temperature, and then cooling, wherein either the electrode portions or the connection terminal portions further have a metal multilayer film containing a second metal and a third metal located between the first metal and the second metal, the first temperature is lower than the solidus temperature of the second metal, and the second temperature is higher than or equal to the solidus temperature of the second metal and lower than or equal to the liquidus temperature. [Effects of the Invention]

[0007] This invention provides a manufacturing method for light-emitting devices that achieves high mounting accuracy and strong bonding when mounting semiconductor light-emitting elements, and involves a short process. [Brief explanation of the drawing]

[0008] [Figure 1] This is a flowchart showing a method for manufacturing a light-emitting device according to the first embodiment. [Figure 2] This is a schematic side view of a semiconductor light-emitting element. [Figure 3] This is a schematic plan view showing a state in which multiple semiconductor light-emitting elements are arranged on a carrier plate via an adhesive layer. [Figure 4]This is a schematic side view showing a state in which multiple semiconductor light-emitting elements are arranged on a carrier plate via an adhesive layer. [Figure 5] This is a schematic longitudinal cross-sectional view of a carrier plate equipped with multiple semiconductor light-emitting elements housed in a tray. [Figure 6] This is a schematic side view showing a method for manufacturing a light-emitting device according to the first embodiment. [Figure 7] This is a schematic top view of the circuit board. [Figure 8] This is a schematic side view of the circuit board. [Figure 9] This is a schematic side view of the connection terminal section of the circuit board. [Figure 10] This is a schematic side view showing a method for manufacturing a light-emitting device according to the first embodiment. [Figure 11] This is an enlarged schematic side view showing a method for manufacturing a light-emitting device according to the first embodiment. [Figure 12] This is a magnified view of the area enclosed by the circle in Figure 11. [Figure 13] This is a schematic side view showing a method for manufacturing a light-emitting device according to the first embodiment. [Figure 14] This is a schematic side view showing a method for manufacturing a light-emitting device according to the first embodiment. [Figure 15] This is a binary phase equilibrium phase diagram for an Au-Sn alloy. [Figure 16] This is a schematic plan view showing a light-emitting device according to the first embodiment. [Figure 17] This is a schematic side view showing a light-emitting device according to the first embodiment. [Figure 18] This is a flowchart showing a method for manufacturing a light-emitting device according to the second embodiment. [Figure 19] This is an enlarged schematic side view showing a method for manufacturing a light-emitting device according to the second embodiment. [Figure 20] This is an enlarged schematic side view showing a method for manufacturing a light-emitting device according to the second embodiment. [Figure 21] This is a flowchart showing a method for manufacturing a light-emitting device according to the third embodiment. [Figure 22]It is a partial enlarged schematic side view of a longitudinal section of a light-emitting device according to a third embodiment.

Embodiments for Carrying out the Invention

[0009] Hereinafter, embodiments of the invention will be described. However, the manufacturing method of the light-emitting device described below is for embodying the technical idea of the present invention, and unless there is a specific description, the present invention is not limited to the following. In addition, the content described in one embodiment is also applicable to other embodiments and modification examples. Furthermore, the sizes and positional relationships of the members shown in the drawings may be exaggerated for clarity of explanation.

[0010] <First Embodiment> The manufacturing method of the light-emitting device according to the first embodiment of the present disclosure includes a temperature-rising step (S101), a temporary bonding step (S102), and a main bonding step (S105), as shown in FIG. 1.

[0011] (Temperature-rising step) In the temperature-rising step (S101), a plurality of semiconductor light-emitting elements 100 are heated to a first temperature lower than the solidus temperature of the second metal 122, and the substrate 200 is also heated to the first temperature. The solidus temperature refers to the temperature at which a substance becomes completely solid at a temperature lower than that. The plurality of semiconductor light-emitting elements 100 include a plurality of electrode portions 120 containing the first metal 121, and the substrate 200 also includes a plurality of connection terminal portions 220 containing the first metal 121. Either one of the electrode portion 120 of the semiconductor light-emitting element 100 or the connection terminal portion 220 of the substrate 200 has a metal multilayer film containing the second metal 122 and a third metal 123 located between the first metal 121 and the second metal 122.

[0012] The semiconductor light-emitting element 100 is a semiconductor device that emits light on its own when an electric current is passed through it, and comprises a semiconductor portion 110 and a plurality of electrode portions 120 connected to the semiconductor portion 110. The dimensions of the semiconductor light-emitting element 100 are, for example, 10.95 μm thick and 50 μm square. Specifically, the semiconductor portion 110 is, for example, 8 μm thick and 50 μm square, and each of the plurality of electrode portions 120 is, for example, 2.95 μm thick, 42 ​​μm long and 18 μm wide. The semiconductor light-emitting element 100 is, for example, a light-emitting diode chip that can be mounted as a flip chip, and comprises a semiconductor portion 110 and positive and negative electrode portions 120 on the lower surface of the semiconductor portion 110, with the upper surface opposite the lower surface being the light extraction surface. Examples of light-emitting diode chips include blue light-emitting diode chips that can emit blue light, green light-emitting diode chips that can emit green light, red light-emitting diode chips that can emit red light, ultraviolet light-emitting diode chips that can emit ultraviolet light, and infrared light-emitting diode chips that can emit infrared light.

[0013] The semiconductor portion 110, although not shown, comprises a semiconductor laminate including a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer located between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer. The active layer generates light through direct recombination of electrons and holes within it. The semiconductor portion 110 may include an element substrate on the light extraction side of the semiconductor laminate. The semiconductor laminate may have tunnel junction layers between two or more active layers. In this case, there will be three or more electrode portions 120. The semiconductor laminate can be composed of, for example, III-V compound semiconductors, i.e., crystals of InAlGaAs-based semiconductors, InAlGaP-based semiconductors, zinc sulfide, zinc selenide, or InAlGaN-based semiconductors.

[0014] In the example shown in Figure 2, each of the multiple electrode portions 120 of the semiconductor light-emitting element 100 has a multilayer metal film containing a first metal 121, a second metal 122, and a third metal 123 located between the first metal 121 and the second metal 122, with the first metal 121 exposed at the tip of each electrode portion 120. The melting point of the first metal 121 is higher than the liquidus temperature of the second metal 122, and the melting point of the third metal 123 is also higher than the liquidus temperature of the second metal 122. The liquidus temperature is the temperature at which a substance becomes completely liquid above that temperature. The first metal 121 contains a metal that is resistant to rust in air, such as the precious metal gold (Au), the second metal 122 contains tin (Sn), and the third metal 123 contains one of the platinum group metals: ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt). The first metal 121 prevents oxidation of the second metal containing Sn, enabling good bonding in air. The third metal 123 reduces the diffusion of components of the second metal 122 into the first metal 121 of the electrode portion 120 during storage before the heating process (S101) or during heating to the first temperature and while holding at the first temperature in the heating process (S101), thereby reducing the rate of pressure welding defects in the temporary bonding process (S102) described later.

[0015] Each electrode portion 120 is a multilayer metal film in which, for example, titanium (Ti) (thickness 0.003 μm to 0.015 μm) is sequentially layered from the semiconductor portion 110 side, a platinum group metal (thickness 0.1 μm to 2 μm), Au (thickness 0.1 μm to 1 μm), an Au-Sn alloy with 15% to 37% Sn by weight (thickness 0.5 μm to 3 μm), Pt (thickness 0.0004 μm to 0.05 μm, preferably 0.02 μm to 0.05 μm), and Au (thickness 0.0004 μm to 0.1 μm). In this case, the first metal 121 is Au layered on Pt, the second metal 122 is an Au-Sn alloy, and the third metal 123 is Pt located between the first metal 121 and the second metal 122. The first metal 121 is exposed at the tip of each electrode portion 120.

[0016] By using an Au-Sn alloy with 15% to 37% by weight of Sn as the second metal 122, the bonding time is shorter and the composition after bonding is more stable compared to when the second metal 122 is Sn. This is because AuSn4 and AuSn2 are not formed by the reaction between the second metal 122 and the Au of the first metal 121. The composition of the Au-Sn alloy of the second metal 122 is preferably 20% to 32% by weight of Sn, and more preferably 26% to 32% by weight of Sn. This is because when bonding multiple semiconductor light-emitting elements, if there is variation in the diffusion of Au in the first metal 121 within the plane of the substrate 200, the slope of the liquidus line is steeper in compositions with more Au than 20% by weight of Sn, resulting in variations in bonding for each semiconductor light-emitting element. Furthermore, it is preferable to select the thickness of the Au in the first metal 121 and the composition and thickness of the Au-Sn alloy of the second metal 122 such that, after this bonding, the ratio of the Sn weight to the Au weight contained in the region including the electrode portion 120 and the connecting terminal portion 220, that is, the connecting metal 130 described later, is 0.25 or more and less than 0.58. More preferably, after this bonding, the ratio of the Sn weight to the Au weight contained in the connecting metal 130 is 0.25 or more and less than 0.408. This reduces the rate of short-circuit failures in this bonding process (S105) and reduces the generation of voids inside the connecting metal 130.

[0017] The thickness of the first metal 121 of the electrode portion 120 is adjusted to be between 0.0004 μm and 0.1 μm. The thickness of the third metal 123 is adjusted to be between 0.0004 μm and 0.05 μm, preferably between 0.02 μm and 0.05 μm. In the bonding process (S105) described later, the first metal 121 and the third metal 123 mix with the second metal 122, so that the first metal 121 and the third metal 123 do not remain as layers after the bonding process (S105).

[0018] Multiple semiconductor light-emitting elements 100 are arranged on the main surface of the carrier plate 300 via an adhesive layer 310, with two or more electrode portions 120 of each element facing upwards, as shown in Figures 3 and 4. The arrangement of the electrode portions 120 of the multiple semiconductor light-emitting elements 100 corresponds to the arrangement of the multiple connection terminal portions 220 of the substrate 200 during the alignment process in the temporary bonding step (S102) described later.

[0019] On a single carrier plate 300, a total of one million 50 μm square semiconductor light-emitting elements 100 can be arranged in a thousand rows and thousand columns, corresponding to the arrangement of multiple connection terminals 220 on the substrate 200. Let's take the example where the carrier plate 300 is, for example, a 70 mm square, 1 mm thick plate made of quartz glass, and the substrate 200 is an 8-inch silicon (Si) wafer. In this case, when the temperature is raised from room temperature of around 20°C to a first temperature of 160°C, the diameter of the substrate 200 increases by approximately 0.1 mm, but the length of one side of the carrier plate 300 increases by only approximately 5 μm. The difference of approximately 100 μm between the increase in the dimensions of the substrate 200 and the increase in the dimensions of the carrier plate 300 is large compared to a 50 μm square semiconductor light-emitting element 100. In other words, it is necessary to arrange the multiple semiconductor light-emitting elements 100 on the carrier plate 300 while taking into account in advance the difference in dimensional changes due to thermal expansion of the carrier plate 300 and the substrate 200 caused by the temperature difference between the temperature when the multiple semiconductor light-emitting elements 100 are placed on the carrier plate 300 and the first temperature. This is to connect each electrode portion 120 of the multiple semiconductor light-emitting elements 100 and the multiple connection terminal portions 220 of the substrate 200 all at once.

[0020] A light-shielding resin or a reflective resin may be placed between the multiple semiconductor light-emitting elements 100. Alternatively, a light-transmitting sheet may be placed between the multiple semiconductor light-emitting elements 100 and the adhesive layer 310.

[0021] Multiple carrier plates 300, each containing multiple semiconductor light-emitting elements 100, are prepared. As shown in Figure 5, the semiconductor light-emitting elements 100 are placed with their electrode portions 120 facing downwards, and housed in the recesses of a tray 400 having multiple recesses on its upper surface. As shown in Figure 6, these are placed on the supply stage 720 of the first mounter.

[0022] The first mounter, as shown in Figures 6, 10, and 13, comprises a first camera 711, a position control mechanism 740, a supply stage 720, a suction head 730, a first infrared radiation thermometer 751, a mounting stage 760, a second infrared radiation thermometer 752, and an intermediate stage 770. The first camera 711 outputs an image, including the plan view shape of the carrier plate 300, which contains a plurality of semiconductor light-emitting elements 100 housed in a tray 400 on the supply stage 720, as image data to the position control mechanism 740. The position control mechanism 740 uses the image data to recognize the positions of the four corners of the carrier plate 300 in plan view. The position control mechanism 740 issues position control signals to the suction head 730 and the supply stage 720 to adjust the relative position between the suction head 730 and the supply stage 720.

[0023] The suction head 730 has a mechanism for adsorbing the carrier plate 300 and a mechanism for heating the adsorbed carrier plate 300, such as a built-in heater. As shown in Figure 6, the suction head 730 adsorbs the carrier plate 300 from the tray 400 on the supply stage 720 to a predetermined position on its lower surface and lifts it from the supply stage 720. The multiple semiconductor light-emitting elements 100 on the lifted carrier plate 300 are heated by the built-in heater of the suction head 730 to a first temperature and held at the first temperature. The temperature of the semiconductor light-emitting elements 100 can be measured, for example, using a first infrared radiation thermometer 751 located below the lower surface of the suction head 730, and the temperature of the semiconductor light-emitting elements 100 is adjusted using PID control (Proportional-Integral-Differential Controller) based on the temperature measured by the first infrared radiation thermometer 751. If the temperature difference between the measured temperature of the semiconductor light-emitting elements 100 and the set first temperature is less than 5°C, the temperature of the semiconductor light-emitting elements 100 can be considered to be substantially the first temperature.

[0024] The first temperature is above room temperature and below the solidus temperature of the second metal 122; that is, at the first temperature, the second metal 122 is solid. When the second metal 122 is an Au-Sn alloy containing 11% to 37% by weight of Sn, the first temperature is, for example, 120°C to 220°C, more preferably 150°C to 190°C.

[0025] In the above, the adsorption head 730 lifts the multiple semiconductor light-emitting elements 100 via the carrier plate 300, raises their temperature to a first temperature, and holds them at that temperature. However, other methods are also possible. For example, the adsorption head 730 of the first mounter may directly adsorb and lift the multiple semiconductor light-emitting elements 100 without using the carrier plate 300, raise their temperature to a first temperature, and hold them at that temperature. In this case, a tray 400 for housing the multiple semiconductor light-emitting elements 100 is placed on the supply stage 720 of the first mounter, and the multiple semiconductor light-emitting elements 100 are arranged in the tray 400 at predetermined intervals with their electrode portions 120 facing downwards.

[0026] As shown in Figures 7 to 9, the substrate 200 includes a base body 210 and a plurality of connection terminals 220 on the upper surface of the base body 210. The substrate 200 may be an integrated circuit (IC) wafer or IC chip containing many elements with functions such as transistors, resistors, and capacitors, or it may be a circuit board such as a printed circuit board. The base body 210 may be a single crystal wafer or a ceramic plate, and may be a substrate material used for circuit boards. The single crystal wafer contains at least one single crystal of Si, germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), gallium nitride (GaN), aluminum nitride (AlN), silicon carbide (SiC), or sapphire. Examples of ceramic plates are AlN, Al2O3, SiC, and Si3N4. The base body 210 may have conductive wiring on the side on which the semiconductor light-emitting element is mounted and on the opposite side, and may also have vias (Vertical Interconnect Accesses).

[0027] The multiple connection terminals 220 are joined to the multiple electrode portions 120 of the semiconductor light-emitting element 100, and are therefore arranged in a manner corresponding to the multiple electrode portions 120 of the semiconductor light-emitting element 100. The area of ​​each connection terminal 220, as viewed from the direction normal to the main surface of the substrate 200, is greater than or equal to the area of ​​the opposing electrode portion 120. Each of the multiple connection terminals 220 can be constructed by laminating multiple metal layers. The first metal 121 is exposed on the surface of the multiple connection terminals 220 that is in contact with the multiple electrode portions 120 of the semiconductor light-emitting element 100.

[0028] The substrate 200 is, for example, an 8-inch IC wafer containing a single-crystal silicon wafer. Its multiple connection terminal portions 220 correspond to the multiple electrode portions 120 of each of the multiple semiconductor light-emitting elements 100. The connection terminal portion 220 includes a first metal 121 exposed at its tip. Each connection terminal portion 220 is constructed by sequentially stacking, for example, Ti (thickness 0.003 μm to 0.015 μm), Pt (thickness 0.1 μm to 2 μm), and Au (thickness 0.1 μm to 1 μm), with Au exposed at the tip. Au becomes the first metal 121 of the connection terminal portion 220.

[0029] The thickness of the first metal 121 of the connection terminal portion 220 is adjusted to be between 0.1 μm and 1 μm, so that in the main bonding process (S105) described later, the first metal 121 mixes with the second metal 122 and no layer of the first metal 121 remains after the main bonding process (S105).

[0030] The substrate 200 is placed on the mounting stage 760 with the multiple connection terminals 220 facing upwards. The surface of the mounting stage 760 on which the substrate 200 is placed is made of flat Si. The mounting stage 760 includes a mechanism for holding the substrate 200 and a mechanism for heating the held substrate 200. The mechanism for holding the substrate 200 may be, for example, a clip or suction. The mechanism for heating the substrate 200 may be, for example, a built-in heater.

[0031] In parallel with, or prior to, raising the temperature of the semiconductor light-emitting element 100, the substrate 200 placed on the mounting stage 760 is also heated by the built-in heater of the mounting stage 760 to a first temperature, for example, 160°C, and maintained at the first temperature. The temperature of the substrate 200 on the mounting stage 760 can be measured, for example, using a second infrared radiation thermometer 752 provided above the mounting stage 760, as shown in Figure 10, and the temperature of the substrate 200 is adjusted by PID control using the temperature measured by the second infrared radiation thermometer 752. If the temperature difference between the measured temperature of the substrate 200 and the set first temperature is less than 5°C, the temperature of the substrate 200 can be considered to be substantially the same as the first temperature.

[0032] In the above, the electrode portion 120 of the semiconductor light-emitting element 100 is assumed to have a metal multilayer film containing the second metal 122 and the third metal 123. However, the connection terminal portion 220 of the substrate 200 may also have a metal multilayer film containing the second metal 122 and the third metal 123. In this case, the electrode portion 120 of the semiconductor light-emitting element 100 does not have the second metal 122. This is because the second metal 122 only needs to be included in either the electrode portion 120 or the connection terminal portion 220.

[0033] (Temporary joining process) In the temporary joining process (S102), after aligning the electrode portion 120 and the connection terminal portion 220, which are held at a first temperature, the first metal 121 of the electrode portion 120 and the first metal 121 of the connection terminal portion 220 are pressed together with a first pressure.

[0034] The second camera 712 outputs an image to the position control mechanism 740 as image data, including the rectangular shape of the outer edge in a plan view of the position identification alignment marks located outside the area where the multiple connection terminals 220 of the substrate 200 are located. The position control mechanism 740 uses the image data to recognize the positions of the multiple connection terminals 220 of the substrate 200.

[0035] When the suction head 730 is moved upward on the mounting stage 760, the position control mechanism 740 adjusts the relative position between the suction head 730 and the mounting stage 760, aligning the multiple electrode portions 120 with their corresponding multiple connection terminal portions 220. Subsequently, the suction head 730 is moved downward to place the carrier plate 300, which includes multiple semiconductor light-emitting elements 100, onto the substrate 200 on the mounting stage 760. At this time, the electrode portions 120 of the semiconductor light-emitting elements 100 are held at a first temperature, and the connection terminal portions 220 of the substrate 200 are also held at a first temperature. As shown in Figures 11 and 12, the first metal 121 of the electrode portion 120 and the first metal 121 of the connection terminal portion 220 are brought into contact and pressed together with a first pressure. This state is held for a first time, pressing the first metal 121 of the electrode portion 120 and the first metal 121 of the connection terminal portion 220 into contact.

[0036] Pressure welding is a type of pressure welding that joins metal surfaces together by applying heat and pressure without melting the joint, keeping them in a solid state. It is also called solid-state joining or solid-state welding. The first pressure is the load (in Newtons, N) that presses the suction head 730 against the mounting stage 760, and the area (in square meters, m) of the multiple electrode parts 120 of the semiconductor light-emitting element 100. 2 It is the value obtained by dividing by the sum of ( ) (unit: Pascals, Pa).

[0037] The first temperature is, for example, 160°C. The first pressure is between 3 MPa and 90 MPa, for example, 45 MPa. The first time is between 1 second and 60 seconds, for example, 10 seconds.

[0038] Since multiple semiconductor light-emitting elements 100 and the substrate 200 are aligned and in contact while being considered to be at the same temperature, the occurrence of relative misalignment of the electrode portion 120 and connection terminal portion 220 caused by the difference in the coefficient of linear expansion between the substrate 200 and the carrier plate 300 is reduced. Since the electrode portion 120 and the connection terminal portion 220 are joined while still solid, the deformation of the electrode portion 120 and the connection terminal portion 220 when pressed is small, and the mounting of multiple semiconductor light-emitting elements 100 onto the substrate 200 can be achieved with high mounting accuracy. In addition, it is efficient because multiple semiconductor light-emitting elements 100 can be pressed together simultaneously.

[0039] A preliminary bonding process (S102) is performed on all of the carrier plates 300, each containing multiple semiconductor light-emitting elements 100, which are housed in a single tray 400 placed on the supply stage 720 of the first mounter, to form an intermediate body 500. The intermediate body 500 includes the carrier plate 300, the multiple semiconductor light-emitting elements 100, and the substrate 200, with the first metal 121 of the electrode portion 120 of the semiconductor light-emitting element 100 and the first metal 121 of the connection terminal portion 220 of the substrate 200 being press-fitted.

[0040] After the substrate 200 is released, the intermediate 500 is lifted from the mounting stage 760 by the suction head 730 on the carrier plate 300 side, as shown in Figure 13, and moved onto the intermediate stage 770.

[0041] (Main joining process) In this bonding process (S105), a second pressure is applied between the multiple semiconductor light-emitting elements 100 and the substrate 200 to bring the intermediate 500 to a second temperature, and then the intermediate 500 is cooled. The second temperature is above the solidus temperature and below the liquidus temperature of the second metal 122. The second pressure is below the first pressure.

[0042] The second mounter comprises a heating head 780 and a base 790. The heating head 780 attracts and lifts the carrier plate 300 side of the intermediate 500. Then, the heating head 780 holding the intermediate 500 is moved downward and, with a second pressure less than or equal to the first pressure applied in the temporary bonding process (S102), the intermediate 500 is pressed against the base 790, as shown in Figure 14, thereby applying a second pressure between the multiple semiconductor light-emitting elements 100 and the substrate 200. The second pressure is between 0.1 MPa and 90 MPa, for example, 45 MPa.

[0043] Then, the heating head 780 and the base 790 are heated to a second temperature, held for a second time, and then cooled to room temperature. The second temperature is, for example, 279°C to 400°C, more preferably 300°C to 330°C, for example 320°C. The second time is longer than the first time, 300 seconds or less, for example 180 seconds.

[0044] In the above, the intermediate 500 was heated using the heating head 780 and base 790, but the intermediate 500 can also be placed in an oven at a second temperature for a second time. In that case, a weight should be placed on the carrier plate 300 so that a second pressure is applied to the intermediate 500.

[0045] At the second temperature, the second metal 122 has both a liquid phase and a solid phase. The presence of the solid phase reduces the spreading of the second metal 122 when pressed with the second pressure, thus lowering the rate of short-circuit failures between the electrode portions 120.

[0046] If the second metal 122 is, for example, an Au-Sn alloy layer with 29 wt% Sn, then according to the binary phase equilibrium phase diagram of the Au-Sn alloy (Figure 15), when the second temperature is 320°C, the solid-phase intermetallic compound AuSn (δ phase, 50 at% Sn) and the liquid-phase Au-Sn alloy with approximately 23 wt% Sn coexist.

[0047] The first metal 121 of the electrode portion 120 and the first metal 121 and third metal 123 of the connecting terminal portion 220 mix with the second metal 122 and then solidify to form the connecting metal 130. The connecting metal 130 connects the semiconductor portion 110 and the substrate 210. When the first metal 121 is Au and the third metal 123 is Pt, a solid phase containing a Pt-Au-Sn alloy and an Au-Sn alloy is formed inside the connecting metal 130. Neither a layer consisting only of Au nor a layer consisting only of Pt remains inside the connecting metal 130. The Au-Sn alloy, which has a relatively low liquidus temperature, covers the Pt-Au-Sn alloy and is exposed on the side surface of the connecting metal 130. The interface between the Au-Sn alloy and the Pt-Au-Sn alloy has a complex, intricate shape. The connecting metal 130 is bound between the semiconductor portion 110 and the substrate 210. The position where the constriction occurs is closer to the substrate 210 than the semiconductor portion 110 when the second metal 122 is included in the electrode portion 120, and closer to the semiconductor portion 110 than the substrate 210 when the second metal 122 is included in the connection terminal portion 220. This is because, since the second temperature is above the solidus temperature and below the liquidus temperature, there is a solid phase portion of δ-phase AuSn in the second metal 122, and a certain distance is maintained between the semiconductor portion 110 and the substrate 210, forming a gap between the semiconductor portion 110 and the substrate 210, while the liquid phase portion wets and spreads.

[0048] Since multiple carrier plates 300 on which multiple semiconductor light-emitting elements 100 are arranged are processed simultaneously, this method is suitable for mass production of light-emitting devices. By raising the temperature to a lower second temperature, which is above the solidus temperature and below the liquidus temperature of the second metal 122, and then cooling it, a greater bonding strength than that achieved by pressure welding is obtained. Since the second pressure is less than or equal to the first pressure, and the electrode portion 120 of the semiconductor light-emitting element 100 and the connection terminal portion 220 of the substrate 200 are pressure-welded before heating, the relative positional relationship between the electrode portion 120 and the connection terminal portion 220 does not change or changes only slightly, enabling high mounting accuracy. Therefore, compared to manufacturing methods using wet plating, there is no patterning or plating process, and the process can be shortened.

[0049] After the bonding process (S105), the multiple carrier plates 300 are peeled off and removed together with the adhesive layer 310, and then the substrate 200 is cut to simultaneously create multiple light-emitting devices as shown in Figures 16 and 17. For example, dicing can be used as the cutting method.

[0050] <Second Embodiment> The method for manufacturing the light-emitting device according to the second embodiment is the same as that of the first embodiment up to the temporary bonding step (S102). As shown in Figure 18, the method for manufacturing the light-emitting device according to the second embodiment includes an inspection step (S103) after the temporary bonding step (S102) and before the main bonding step (S105). Furthermore, the method for manufacturing the light-emitting device according to the second embodiment includes a repair step (S104) if there are semiconductor light-emitting elements 100 that are determined to have failed the inspection. In the second embodiment, the object to be inspected 510 includes a plurality of semiconductor light-emitting elements 100 and a substrate 200, and the first metal 121 of the electrode portion 120 of the semiconductor light-emitting element 100 and the first metal 121 of the connection terminal portion 220 of the substrate 200 are press-fitted together.

[0051] (Inspection process) After the temporary bonding process (S102), the carrier plate 300 and adhesive layer 310 are peeled off and removed to obtain the object to be inspected 510. Then, each of the multiple semiconductor light-emitting elements 100 is irradiated with excitation light, and a photoluminescence inspection is performed to measure the emission intensity and spectrum of each semiconductor light-emitting element 100. The excitation light has a wavelength that generates electron-hole pairs in the active layer of the semiconductor part 110. Photoluminescence inspection is a method of irradiating a material with light and observing the light generated when the photo-excited electrons return to the ground state. Semiconductor light-emitting elements 100 that show measurement values ​​outside a predetermined numerical range are judged to have failed the inspection, and their positions are stored in a memory device.

[0052] Although photoluminescence testing was used in the above method, if the substrate 200 is provided with wiring for supplying power to multiple semiconductor light-emitting elements 100, each semiconductor light-emitting element 100 may be made to emit light by supplying power, and its emission intensity and spectrum may be measured.

[0053] (Repair process) In the inspection process (S103), the semiconductor light-emitting element 100 at the position stored in the memory device is removed from the object to be inspected 510. At this time, as shown in Figure 19, the connection terminal portion 220 of the substrate 200 that was in contact with the electrode portion 120 of the removed semiconductor light-emitting element 100 remains on the object to be inspected 510. Methods for removal include, for example, using an adsorption collet, irradiating with laser light, or using an adhesive sheet.

[0054] Next, the object 510, after the semiconductor light-emitting element 100 that failed the inspection has been removed, is returned to the mounting stage 760 and heated to the first temperature. In parallel, a new semiconductor light-emitting element 100 is positioned using the suction collet 731, lifted, and heated to the first temperature. Then, as shown in Figure 20, the electrode portion 120 of the new semiconductor light-emitting element 100 is aligned with the connection terminal portion 220 of the substrate 200 in the area where the semiconductor light-emitting element 100 that failed the inspection was removed and pressed into place, thereby replacing the old semiconductor light-emitting element 100 with a new one.

[0055] The newly bonded semiconductor light-emitting element 100 is made to emit light, and it is checked whether or not any of the semiconductor light-emitting elements 100 show a measurement value outside a predetermined numerical range. If no semiconductor light-emitting elements 100 are determined to have failed the inspection, the process proceeds to the main bonding process (S105). If any semiconductor light-emitting elements 100 are determined to have failed the inspection, the repair process (S104) and the inspection process (S103) are repeated until there are no more semiconductor light-emitting elements 100 determined to have failed the inspection. By including the inspection process (S103) and the repair process (S104), the illumination rate of multiple semiconductor light-emitting elements 100 in a single light-emitting device can be made 100%, or close to 100%.

[0056] <Third Embodiment> The manufacturing method of the light-emitting device according to the third embodiment is the same as that of the first or second embodiment up to the bonding step (S105). As shown in Figure 21, after the bonding step (S105), the manufacturing method of the light-emitting device according to the third embodiment includes an underfill step (S106) in which, after peeling off and removing the multiple carrier plates 300 together with the adhesive layer 310, the gap between the semiconductor part 110 and the substrate 210 is filled and sealed with underfill 600. This is to reinforce the connection between the semiconductor light-emitting element 100 and the substrate 200. The underfill 600 also has the function of protecting the connecting metal 130 from external moisture, etc.

[0057] The material for underfill 600 preferably has low viscosity, low thixotropy, defoaming properties, and wettability before curing, and after curing, it preferably has high adhesive strength, toughness, moderate flexibility, low coefficient of thermal expansion, and a high glass transition temperature. Before curing, Underfill 600 contains resin material, as well as fillers and diluents.

[0058] Resin materials used in Underfill 600 include epoxy resin, silicone resin, modified silicone resin, polyurethane resin, oxetane resin, acrylic resin, polycarbonate resin, polyimide resin, and polyester resin. Thermosetting resins such as silicone resin, modified silicone resin, and epoxy resin, which have good light transmission properties, are preferred.

[0059] The filler preferably contains particles of inorganic materials such as titanium dioxide, aluminum oxide, zinc oxide, barium carbonate, barium sulfate, boron nitride, aluminum nitride, and glass filler in order to impart light reflectivity to the underfill 600. The median diameter of these particles is preferably between 1 nm and 200 nm, more preferably 100 nm or less, and particularly preferably 50 nm or less. The ratio of the filler to the resin material is adjusted to control the thermal expansion coefficient of the underfill 600 after curing.

[0060] Organic solvents such as aliphatic hydrocarbon solvents (tridecane, heptane, hexane, etc.), aromatic hydrocarbon solvents (xylene, toluene, benzene, etc.), halogenated hydrocarbon solvents (trichloroethylene, perchloroethylene, methylene chloride, etc.), ester solvents (ethyl acetate, etc.), ketone solvents (methyl isobutyl ketone, methyl ethyl ketone, etc.), and alcohol solvents (ethanol, isopropanol, butanol, etc.) can be used as diluents. The boiling point of the diluent is preferably between 100°C and 350°C, but more preferably between 150°C and 300°C. The diluent is used to reduce the viscosity of the underfill 600 before curing, among other things.

[0061] The underfill 600, before curing, is supplied around multiple semiconductor parts 110 on the upper surface of the substrate 210. The gaps between the semiconductor parts 110 and the substrate 210 are filled with the underfill 600 using capillary action. Subsequently, the resin material contained in the underfill 600 is heat-cured. After that, the circuit board 200 is cut to create multiple light-emitting devices simultaneously.

[0062] As shown in Figure 22, after the underfill process (S106), the underfill 600 is positioned in contact with the lower surface of the semiconductor part 110, the upper surface of the substrate 210, and the side surface of the connecting metal 130. Since the connecting metal 130 is bound between the semiconductor part 110 and the substrate 210, recessed areas are formed on the side surface of the connecting metal 130, and the intersection line between the side surface of the connecting metal 130 and the longitudinal cross-section includes a sharp bend. The underfill 600 fills into these recessed areas and hardens, resulting in an anchoring effect. This enhances the function of the underfill 600 in reinforcing the connection between the semiconductor light-emitting element 100 and the substrate 200.

[0063] This disclosure includes the following components. (Section 1) A heating step to bring a plurality of semiconductor light-emitting elements, each having an electrode portion containing a first metal, and a substrate having a plurality of connection terminal portions containing the first metal, to a first temperature; After aligning the electrode portion and the connection terminal portion while maintaining the first temperature, a temporary joining step is performed to press the first metal of the electrode portion and the first metal of the connection terminal portion together with a first pressure to form an intermediate body. The bonding process involves applying a second pressure, less than or equal to the first pressure, between a plurality of semiconductor light-emitting elements and the substrate, bringing the intermediate to a second temperature, and then cooling it. Equipped with, Either the electrode portion or the connection terminal portion further has a metal multilayer film comprising a second metal and a third metal located between the first metal and the second metal, The first temperature is lower than the solidus temperature of the second metal. The second temperature is above the solidus temperature of the second metal and below the liquidus temperature. A method for manufacturing a light-emitting device. (Section 2) In the main bonding step, the second time for applying the second pressure between the plurality of semiconductor light-emitting elements and the substrate is longer than the first time for pressing them together in the temporary bonding step. A method for manufacturing the light-emitting device described in item (1) above. (Section 3) The first pressure is 3 MPa or more and 90 MPa or less, and the second pressure is 0.1 MPa or more and 90 MPa or less. A method for manufacturing a light-emitting device as described in item (1) or item (2) above. (Section 4) The first metal is Au, the second metal is an Au-Sn alloy containing 26% to 32% by weight of Sn, and the third metal contains one of Ru, Rh, Pd, Os, Ir, or Pt. A method for manufacturing a light-emitting device according to any one of the above items (1) to (3). (Section 5) The first temperature is 150°C or higher and 190°C or lower, and the second temperature is 300°C or higher and 330°C or lower. A method for manufacturing the light-emitting device described in item (4) above. (Section 6) Between the preliminary bonding step and the final bonding step, the system includes an inspection step for inspecting and determining the semiconductor light-emitting element, and a repair step for replacing the semiconductor light-emitting element that was determined to fail the inspection step. A method for manufacturing a light-emitting device according to any one of the above items (1) to (5). (Section 7) The substrate includes a base body, and the upper surface of the base body is provided with a plurality of connection terminal portions. The semiconductor light-emitting element includes a semiconductor portion, and the electrode portion is provided on the lower surface of the semiconductor portion. After the bonding process described above, the system includes an underfilling step in which the gap between the semiconductor portion and the substrate is filled with underfill. A method for manufacturing a light-emitting device according to any one of the above items (1) to (6). (Section 8) A semiconductor part that generates light, Substrate and, A connecting metal that connects the semiconductor part and the substrate, The underfill is disposed in contact with the lower surface of the semiconductor portion, the upper surface of the substrate, and the side surface of the connecting metal, In the longitudinal section, the connecting metal is constricted. Light-emitting device. (Section 9) The light-emitting device according to item (8), wherein the connecting metal comprises Au and Sn, and the ratio of the weight of Sn to the weight of Au contained in the connecting metal is 0.25 or more and less than 0.408. [Explanation of Symbols]

[0064] 100 Semiconductor light-emitting element, 110 Semiconductor part, 120 Electrode part, 121 First metal, 122 Second metal, 123 Third metal, 130 Connecting metal, 200 Substrate, 210 Base body, 220 Connection terminal part, 300 Carrier plate, 310 Adhesive layer, 400 Tray, 500 Intermediate, 510 Inspection target, 600 Underfill, 711 First camera, 712 Second camera, 720 Supply stage, 730 Suction head, 731 Suction collet, 740 Position control mechanism, 751 First infrared radiation thermometer, 752 Second infrared radiation thermometer, 760 Mounting stage, 770 Intermediate stage, 780 Heating head, 790 Base

Claims

1. A heating step to bring a plurality of semiconductor light-emitting elements, each having an electrode portion containing a first metal, and a substrate having a plurality of connection terminal portions containing the first metal, to a first temperature; After aligning the electrode portion and the connection terminal portion while maintaining the first temperature, a temporary joining step is performed to press the first metal of the electrode portion and the first metal of the connection terminal portion together with a first pressure to form an intermediate body. The bonding process involves applying a second pressure, less than or equal to the first pressure, between a plurality of semiconductor light-emitting elements and the substrate, bringing the intermediate to a second temperature, and then cooling it. Equipped with, Either the electrode portion or the connection terminal portion further comprises a metal multilayer film including a second metal and a third metal located between the first metal and the second metal. The first temperature is lower than the solidus temperature of the second metal. The second temperature is above the solidus temperature of the second metal and below the liquidus temperature. A method for manufacturing a light-emitting device.

2. The method for manufacturing a light-emitting device according to claim 1, wherein the second time for applying the second pressure between the plurality of semiconductor light-emitting elements and the substrate in the main bonding step is longer than the first time for pressing them together in the temporary bonding step.

3. A method for manufacturing a light-emitting device according to claim 1, wherein the first metal is Au, the second metal is an Au-Sn alloy containing 26% by weight or more and 32% by weight or less of Sn, and the third metal contains one of Ru, Rh, Pd, Os, Ir, and Pt.

4. A method for manufacturing a light-emitting device according to claim 3, wherein the first temperature is 150°C or more and 190°C or less, and the second temperature is 300°C or more and 330°C or less.

5. The method for manufacturing a light-emitting device according to claim 1, wherein the first pressure is 3 MPa or more and 90 MPa or less, and the second pressure is 0.1 MPa or more and 90 MPa or less.

6. A method for manufacturing a light-emitting device according to claim 1, further comprising an inspection step for inspecting and determining the semiconductor light-emitting element and a repair step for replacing the semiconductor light-emitting element that was determined to have failed the inspection in the inspection step, between the provisional bonding step and the main bonding step.

7. A method for manufacturing a light-emitting device according to claim 1, wherein the substrate includes a base body, and a plurality of connection terminal portions are provided on the upper surface of the base body, the semiconductor light-emitting device includes a semiconductor portion, and the electrode portion is provided on the lower surface of the semiconductor portion, and after the bonding step, an underfill step is provided in which the gap between the semiconductor portion and the base body is filled with underfill.

8. A semiconductor part that generates light, Substrate and, A connecting metal that connects the semiconductor part and the substrate, The underfill is disposed in contact with the lower surface of the semiconductor portion, the upper surface of the substrate, and the side surface of the connecting metal, In the longitudinal section, the connecting metal is constricted. Light-emitting device.

9. The light-emitting device according to claim 8, wherein the connecting metal comprises Au and Sn, and the ratio of the weight of Sn to the weight of Au contained in the connecting metal is 0.25 or more and less than 0.408.

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