JP7402706B2 - Method for manufacturing a light emitting device, and light emitting device - Google Patents

Description

The present invention relates to a method for manufacturing a light emitting device and a light emitting device.

A light-emitting device has been proposed in which a plurality of light-emitting bodies are arranged on a resin and two adjacent light-emitting bodies among the plurality of light-emitting bodies are electrically connected by wiring (see Patent Document 1).

Japanese Patent Application Publication No. 2015-056650

In the light emitting device described in Patent Document 1, wiring that electrically connects two adjacent light emitters is shown, but a specific method for forming the wiring is not shown.
There is a demand for lower cost of light emitting devices, and along with this, there is a need for a method of manufacturing the wiring of the light emitting device at lower cost.

According to a first aspect of the present invention, in the method for manufacturing a light emitting device, a plurality of light emitting parts are arranged with their emission surfaces facing the front surface, and a plurality of electrodes connected to the plurality of light emitting parts are arranged on the back surface. The method includes preparing a substrate exposed from the substrate, and forming wiring using conductive paste on the back surface of the substrate to be connected to at least a portion of the electrode.
According to a second aspect of the present invention, in the light emitting device, a plurality of light emitting sections are arranged with their emission surfaces facing the front surface, and a plurality of electrodes connected to the plurality of light emitting sections are exposed from the back surface. and a wiring made of conductive paste and connected to at least a portion of the electrode.

According to the manufacturing method of the present invention, a light emitting device including a plurality of light emitting parts can be manufactured at low cost.

FIGS. 1(a) to 1(c) are diagrams showing a light emitting device according to a first embodiment. FIG. 1(a) is a perspective view of a light emitting device. FIG. 1(b) is a diagram of the light emitting device seen from the back side. FIG. 1(c) is a sectional view taken along line A in FIG. 1(b). FIGS. 2(a) to 2(d) are cross-sectional views illustrating a first embodiment of a method for manufacturing a light emitting device. FIGS. 3(a) to 3(c) are diagrams illustrating a second modification of the method for manufacturing a light emitting device. FIGS. 4(a) to 4(c) are diagrams illustrating a third modification of the method for manufacturing a light emitting device. FIGS. 5(a) to 5(d) are diagrams illustrating a fourth modification of the method for manufacturing a light emitting device. FIGS. 6(a) to 6(d) are cross-sectional views illustrating a second embodiment of a method for manufacturing a light emitting device. 7(a) to 7(c) are cross-sectional views illustrating a second embodiment of the method for manufacturing a light emitting device following FIG. 6. FIG. FIGS. 8(a) to 8(d) are diagrams illustrating a fifth modification of the method for manufacturing a light emitting device. 9(a) to 9(b) are cross-sectional views illustrating a fifth modification of the method for manufacturing a light emitting device following FIG. 8. FIG. FIGS. 10(a) to 10(c) are diagrams illustrating a sixth modification of the method for manufacturing a light emitting device. FIGS. 11A and 11B are diagrams illustrating Modification 7 and Modification 8 of the method for manufacturing a light emitting device.

(One embodiment of a light emitting device)
Hereinafter, a light emitting device 1 of one embodiment will be described with reference to FIGS. 1(a) to 1(c). FIG. 1(a) is a perspective view of the light emitting device 1. FIG. As shown in FIG. 1(a), the light emitting device 1 includes a plurality of light emitting parts 3 arranged in a substrate 2. As an example, the substrate 2 is a rectangular flat plate, and the directions parallel to each side of the rectangle are the X direction and the Y direction. Further, a direction perpendicular to the X direction and the Y direction is defined as the Z direction. In the X direction, Y direction, and Z direction indicated by arrows in FIG. 1(a) and the subsequent figures, the direction indicated by the arrow is the + direction. Further, in each of the subsequent figures, the +X direction, +Y direction, and +Z direction indicate the same directions as in FIG. 1(a).

Hereinafter, the end surface of the substrate 2 in the +Z direction will be referred to as a "front surface" 2f. Further, the end surface of the substrate 2 in the −Z direction is called a back surface 2b (see FIG. 1(b), etc.).
The plurality of light emitting sections 3 are arranged such that an exit surface 4, which is a surface from which light is emitted from the light emitting sections 3, is exposed from the front surface 2f of the substrate 2. The shape of the emission surface 4 is, for example, a rectangle, and the light emitting parts 3 are two-dimensionally arranged along, for example, the X direction and the Y direction.

FIG. 1(b) is a plan view of the light emitting device 1 viewed from the back surface 2b side. On the back surface 2b of the light emitting device 1, electrodes 5 electrically connected to the respective light emitting parts 3 are exposed. Although the light emitting section 3 is not visible from the back surface 2b side, the light emitting section 3 is shown with a broken line in FIG. 1(b) for easy understanding.

Wirings 7a and 7b are formed on the back surface 2b to be electrically connected to the electrode 5 and to supply power to the light emitting section 3 via the electrode 5. Here, the wiring 7a is a wiring for supplying power to the light emitting unit 3 from a power source provided outside the light emitting device 1, and the wiring 7b is a wiring for locally supplying power to the light emitting unit 3 from a power source provided outside the light emitting device 1. This is the wiring to connect to. In this specification, the wiring 7a and the wiring 7b may be collectively referred to as the wiring 7, or each may be referred to as the wiring 7.

FIG. 1(c) is a partial cross-sectional view (XZ cross-sectional view) of the light emitting device 1 along the line segment A shown in FIG. A cross section is shown.
The substrate 2 is mainly made of resin such as silicone resin or epoxy resin, and includes a plurality of light emitting parts 3 inside the substrate 2 .

The light emitting unit 3 includes, for example, a light emitting element 10 including a light emitting diode (LED), a transparent substrate 11 such as sapphire laminated on the light emitting element 10, a fluorescent layer 12 containing a fluorescent substance, and a protective layer 13. . In the light source device 1 of one embodiment, the +Z side surface of the protective layer 13 becomes the emission surface 4 of the light emitting section 3.

The electrode 5 is made of a conductive material such as copper, and its -Z side end surface is flush with the back surface 2b of the substrate 2.
As described above, the wiring 7 electrically connected to the electrode 5 is formed on the back surface 2b. Although not shown in FIG. 1B, an insulating protective film 8 is formed on the back surface 2b, covering at least a portion of the wiring 7. The protective film 8 ensures the insulation of the wiring 7 and prevents short circuits due to migration of the wiring 7. However, if the wiring 7 has sufficient migration resistance, the protective film 8 may be omitted.

Although only one layer of the wiring 7 is shown in FIG. 1(b) and FIG. 1(c), the wiring 7 may be formed in multiple layers of two or more layers, as explained in the manufacturing method described later. It's okay. In that case, a protective film 8 as an insulating layer is disposed at least in part between the layers of each multilayer wiring 7.

In the light emitting device 1 of one embodiment, the wiring 7 is a wiring formed using conductive paste. The conductive paste is made by dispersing powder (filler) made of a conductor such as metal or carbon black in a polymer binder. As the conductive paste used to form the wiring 7, for example, a silver paste containing a silver filler, a copper paste containing a copper filler, a gold paste containing a gold filler, or an aluminum paste containing an aluminum filler can be used. .

In the light emitting device 1 of one embodiment, the wiring 7 can be, for example, formed by forming a conductive paste at a predetermined position on the substrate 2 and sintering a filler, which is a conductor, by heating. Note that various modifications of the light emitting device 1 are constructed by various methods of forming the wiring 7, which will be described later.

On the other hand, conventionally, fine wiring has been formed by lithography. That is, after forming a film of a conductor such as metal over the entire surface of a substrate on which wiring is to be formed, wiring is formed by removing unnecessary portions from the conductor film and leaving necessary portions. Therefore, in the past, a much larger amount of conductor was required than the amount ultimately used as wiring. Further, since the resin constituting the substrate 2 is easily affected by chemical treatments, a treatment to protect the resin is required during etching treatment in the lithography method, which further increases the number of steps and costs.

In the light emitting device 1 of one embodiment, the wiring 7 is formed of a conductive paste, so the amount of conductor such as metal required to form the wiring 7 and the number of required steps are reduced compared to conventional ones. can be reduced. Therefore, the production cost for forming the wiring 7 can be reduced.

Further, since the wiring 7 is formed of conductive paste, the thickness (size in the Z direction) of the wiring 7 can be reduced. Thereby, the overall thickness of the light source device 1 can also be reduced.
On the other hand, the thickness of the entire wiring layer formed by conventional lithography in the Z direction is about 50 to 60 μm if the wiring layer has a two-layer structure, and in the past, it has been impossible to make the light source device sufficiently thin. was difficult.

In the light emitting device 1 of one embodiment, since the wiring 7 is formed of conductive paste, the thickness of each layer of the wiring 7 can be reduced to 10 μm or less. Even if the thickness of the protective film 8 is included, it is 20 μm or less, and if the wiring layer has a two-layer structure, it is 30 μm or less. Therefore, even if the wiring 7 is formed in four layers, the total thickness of the four layers of wiring 7 and the protective film 8 can be reduced to 100 μm or less, making it possible to make the light source device sufficiently thin. can.

(Effects of the light emitting device of one embodiment)
(1) The light emitting device of one embodiment is arranged such that the emission surfaces 4 of the plurality of light emitting parts 3 are exposed from the front surface 2f, and the plurality of electrodes 5 connected to the plurality of light emitting parts 3 are arranged on the back surface 2b. A wiring 7 formed of conductive paste and connected to at least a portion of the electrode 5 is provided.
With this configuration, the amount of conductor such as metal required to form the wiring 7 can be reduced compared to the conventional method, and a low-cost light source device 1 can be realized.

(First embodiment of a method for manufacturing a light emitting device)
The manufacturing method of the first embodiment will be described below with reference to FIGS. 2(a) to 2(c).

(Step 1)
A substrate 2 that is arranged so that the emission surfaces 4 of the plurality of light emitting parts 3 are exposed from the front surface 2f, and formed so that the plurality of electrodes 5 connected to the plurality of light emitting parts 3 are exposed from the back surface 2b. Prepare. That is, the substrate 2 to be prepared is a substrate on which the wiring 7 and the protective film 8 are not formed, unlike the light emitting device 1 of the embodiment shown in FIGS. 1(a) to 1(c).

FIG. 2(a) is a diagram showing an XZ cross section of the substrate 2 to be prepared along line A in FIG. 1(b). Note that FIG. 2(a) is shown with the vertical direction (Z direction) reversed from the above-mentioned FIG. 1(c).
Unlike the light emitting device 1 of the embodiment shown in FIG. 1(c), the wiring 7 and the protective film 8 are not yet formed on the substrate 2 shown in FIG. 2(a).
Note that the substrate 2 is made by, for example, arranging a plurality of light emitting parts 3 on which electrodes 5 are formed in the same plane (in the XY plane) with the emission surfaces 4 facing the +Z direction, and molding them all at once with resin. It can be formed by

(Step 2)
As shown in FIG. 2(b), conductive pastes 6a and 6b are formed on the back surface 2b of the substrate 2 at positions where the wiring 7 is to be formed. The conductive paste 6a is a portion that will become a wiring 7a by sintering, which will be described later, and the conductive paste 6b is a portion that will become a wiring 7b. The conductive paste 6a and the conductive paste 6b may be collectively referred to as the conductive paste 6, or each may be referred to as the conductive paste 6.
As described above, gold paste, silver paste, copper paste, or the like can be used as the conductive paste.

The conductive paste is formed on the back surface 2b of the substrate 2 by, for example, printing the conductive paste 6 all over the back surface 2b at once by screen printing. By printing over the entire back surface 2b at once, the conductive paste 6 can be formed at a high processing speed.

Note that the conductive paste 6 needs to be formed in position alignment with at least a portion of the plurality of electrodes 5 formed on the back surface 2b of the substrate 2. Therefore, prior to forming the conductive paste 6 by screen printing or the like, the positions of the plurality of electrodes 5 in the X direction and the Y direction are detected using a technique such as pattern matching using, for example, an optical position detection device. Then, based on the detected position information, conductive paste 6 is formed in accordance with the position of electrode 5. Regarding the optical position detection device and techniques such as pattern matching, well-known techniques may be used, so description thereof will be omitted.

(Step 3)
The conductive paste 6 formed on the back surface 2b of the substrate 2 is sintered to form the wiring 7. FIG. 2C shows a state in which wiring 7 is formed on the back surface 2b by sintering the conductive paste 6. Sintering is performed by heating the substrate 2 and the conductive paste 6 to about 200°C to 300°C. When using silver paste as the conductive paste, the sintering temperature may be 200° C. or lower.

(Step 4)
A protective film 8 covering at least a portion of the wiring 7 is formed on the back surface 2b of the substrate 2 on which the wiring 7 is formed. FIG. 2(d) shows the substrate 2 on which the protective film 8 is formed. The protective film 8 is formed, for example, by pasting an insulating resin or by printing.
Through the above steps, the light emitting device 1 of one embodiment is completed.

(Effects of the first embodiment of the method for manufacturing a light emitting device)
(2) In the manufacturing method of the first embodiment, the plurality of light emitting parts 3 are arranged with their emission surfaces 4 facing the front surface 2f, and the plurality of electrodes 5 connected to the plurality of light emitting parts 3 are arranged on the back surface 2b. The method includes preparing a substrate 2 formed to be exposed from the substrate 2, and forming a wiring 7 using a conductive paste 6, which is connected to at least a part of the electrode 5, on the back surface 2b of the substrate 2. ing.
With this configuration, the amount of conductive material such as metal required for forming the wiring 7 can be reduced, the wiring 7 can be formed at low cost, and the light emitting device 1 can be manufactured at low cost. .
(3) Furthermore, the manufacturing process is simplified by forming a conductive paste 6 on the back surface 2b of the substrate 2, sintering the formed conductive paste 6, and forming the wiring 7 on the back surface 2b of the substrate 2. At the same time, the light emitting device 1 can be manufactured at low cost.

(Modified example 1 of manufacturing method of light emitting device)
Modification 1 will be described below. Modification 1 has most of the same features as the first embodiment described above. Therefore, the configurations that are different from the first embodiment will be described below, and the description of the common configurations will be omitted as appropriate.

In the first embodiment, in step 2, a method of forming the conductive paste 6 all over the back surface 2b at once, such as screen printing, was used.
On the other hand, in Modified Example 1 of the manufacturing method, the conductive paste 6 is formed on the back surface 2b of the substrate 2 using a dispenser that discharges the conductive paste 6 toward the substrate 2. In this case, the conductive paste 6 may be discharged while one dispenser scans the substrate 2 two-dimensionally relative to the substrate 2. Alternatively, the conductive paste 6 may be discharged while two-dimensionally scanning a plurality of dispensers relative to the substrate 2. Alternatively, the conductive paste 6 may be discharged while relatively scanning the substrate 2 one-dimensionally or two-dimensionally using a so-called inkjet printer head that includes a large number of dispensers.

When forming the conductive paste 6 using a dispenser or an inkjet printer head, the position of the conductive paste 6 on the substrate 2, that is, the position of the wiring 7, can be freely changed by changing the discharge timing in relative scanning. Can be changed. In other words, the plurality of conductive pastes 6 on the substrate 2, that is, the plurality of wirings 7, are formed so that the mutual positional relationship is changed with respect to the designed positional relationship. The design value of the mutual positional relationship may be changed by uniformly expanding or contracting each position of the plurality of conductive pastes 6 as a whole (scaling), or by randomly changing each position of the plurality of conductive pastes 6. It may be changed to
Therefore, even if the substrate 2 is deformed as a whole or locally due to thermal contraction or the like and the electrodes 5 are deviated from the designed position, the By correcting the discharge position of the conductive paste 6, the wiring 7 can be formed in accurate alignment with the electrode 5.

The mutual positional relationship of the conductive pastes 6 corresponding to the wiring 7 may be changed by uniformly expanding and contracting the positions (arrangement intervals) of the plurality of conductive pastes 6 on the substrate 2 as a whole. , a plurality of conductive pastes 6 may be individually and locally displaced.

For the substrate 2 that is locally deformed, by locally displacing and forming each of the plurality of conductive pastes 6, the conductive paste 6 can be accurately applied to each of the electrodes 5 on the substrate 2. They can be formed in alignment.
In this case, the positions of a large number of electrodes 5, for example, about 20% or more of all electrodes 5, are detected, information regarding the displacement of the electrodes 5 is calculated based on the detection results, and each position is determined based on the calculated information. The conductive paste 6 may be locally displaced and aligned with each electrode 5 to be formed.

On the other hand, when forming the conductive paste 6 all at once by screen printing or the like as in the first embodiment, each position of the conductive paste 6 to be formed is fixed by the screen mask used. I cannot change the positional relationship. Therefore, when forming the conductive paste 6 all at once by screen printing or the like, if the substrate 2 deforms irregularly, the wiring 7 It becomes difficult to form and align the positions accurately.

(Effects of modification 1 of the method for manufacturing a light emitting device)
(4) Modification 1 further detects the positional information of the electrodes 5 formed on the first substrate 2 in the first embodiment, and connects at least part of the wiring 7 with each other based on the positional information. Formed by changing the positional relationship of.
With this configuration, the wiring 7 can be formed in each part on the substrate 2 while accurately aligning the position with the electrode 5.

(Modified example 2 of manufacturing method of light emitting device)
Modification 2 will be described below. Modification 2 has most of the same features as Modification 1 described above. Therefore, the configurations that are different from Modification Example 1 will be described below, and the description of common configurations will be omitted as appropriate.

In the second modification, a dispenser or an inkjet printer head is used to form the conductive paste 6 on portions of the wiring 7 that require high positional accuracy. On the other hand, the conductive paste 6 is formed all at once by screen printing or the like for parts of the wiring 7 where the required positional accuracy is not so high.

3(a) to 3(c) are diagrams illustrating the formation process of the conductive paste 6 in Modification 2 of the method for manufacturing a light emitting device, and are views of the substrate 2 viewed from the back surface 2b side.
In the second modification of the manufacturing method, in the step corresponding to step 2 in the first embodiment described above, as in the first embodiment, as shown in FIG. The position of the electrode 5 in the X direction and the Y direction is detected.

Based on the detection result of the position of the electrode 5, as shown in FIG. 3(b), a dispenser or an inkjet printer head is used to place the part where high positional accuracy is required, such as the part connected to the electrode 5. Conductive pastes 6b and 6c are formed in alignment with the electrodes 5.
Subsequently, the conductive paste 6d is formed all at once by screen printing or the like in areas where the required positional accuracy is not so high. Note that a part of the conductive paste 6d overlaps with the previously formed conductive paste 6c, and the conductive paste 6c and the conductive paste 6d are integrated to form the conductive paste 6a.

After forming the conductive paste 6d, the conductive paste 6 (6a to 6d) is sintered to form a wiring 7 similar to that shown in FIG. 1(b).
Note that the conductive paste 6d may be formed at once, and the conductive pastes 6b and 6c may be formed later using a dispenser or an inkjet printer head.
Alternatively, after the previously formed conductive pastes 6b, 6c or 6d are sintered, the conductive pastes 6d or 6b, 6c may be formed later and sintered.

(Effects of modification 2 of the method for manufacturing a light emitting device)
(5) Modification 2 is a modification of Modification 1 described above in which the mutual positional relationship of a part of the wiring 7 (the part corresponding to the conductive pastes 6b and 6c) is changed based on the position information of the electrode 5. At the same time, the other wirings 7 (portions corresponding to the conductive paste 6d) are formed with their mutual positional relationship fixed.
With this configuration, it is possible to realize a manufacturing method that has both high throughput and high position alignment accuracy.

(Variation 3 of manufacturing method of light emitting device)
Modification 3 will be described below. The third modification has most of the same features as the first embodiment described above. Therefore, the configurations that are different from the first embodiment will be described below, and the description of the common configurations will be omitted as appropriate.

4(a) to 4(c) are diagrams showing the process of forming the conductive paste 6 in Modification 3, and show cross-sectional views of the substrate 2. FIG.
In modification 3, in a step corresponding to step 2 in the first embodiment, a resist 9 is first formed on the back surface 2b of the substrate 2, as shown in FIG. 4(a). The resist 9 may be a dry film resist pasted by lamination or the like, or may be applied by spin coating or spray coating.

Subsequently, the position of the electrode 5 on the back surface 2b is detected through the resist 9, and a part of the resist 9 is exposed to light based on the detected position information of the electrode 5, thereby removing a part of the resist 9.
FIG. 4(b) is a diagram showing the resist 9 with a portion removed, and the groove portion 9o is the portion where the resist 9 is removed. The groove portion 9o may be a portion where the resist 9 is removed by development after exposure, or may be a portion where the resist 9 is sublimated and removed by exposure.

As shown in FIG. 4(c), the groove portion 9o, which is the portion where the resist 9 has been removed, is filled with conductive paste 6. In this case, by applying the conductive paste 6 to the entire back surface 2b of the substrate 2 covered with the resist 9, the groove 9o can be filled with the conductive paste 6. Note that the conductive paste 6 applied to the back surface 2b but not filled in the groove 9o is recovered and reused to fill the groove 9o of another substrate 2.

Subsequently, as in step 3 of the first embodiment described above, the substrate 2 is heated to sinter the conductive paste 6 to form the wiring 7 (not shown in FIG. 4(c)). Thereafter, by removing the resist 9, the wiring 7 is formed on the back surface 2b similarly to the above-described FIG. 2(c).

Note that in the exposure of the resist 9 to form the groove 9o, as in the above-mentioned modification 1, at least a portion of the groove 9o is exposed to light depending on the displacement of the position of the electrode 5 due to the deformation of the substrate 2. Exposure may be performed by changing the positional relationship between them. For this purpose, the resist 9 may be exposed using a laser beam scanning type exposure device or an exposure device using a variable shaping mask such as a multi-mirror device. Thereby, even if the substrate 2 is deformed, the wiring 7 can be accurately formed by accurately aligning the groove portions 9o with the electrodes 5 at each portion on the substrate 2.

In addition, similar to the above-mentioned modification 2, a laser beam scanning type exposure device is used for the groove portion 9o corresponding to the wiring 7 that requires high positional accuracy, and for the groove portion 9o corresponding to the wiring 7 that does not require high positional accuracy. Alternatively, exposure may be performed using an exposure apparatus that uses a fixed mask.
Note that before removing the resist 9, the conductive paste 6 that may remain on the resist 9 may be removed by polishing.
Note that if a so-called permanent resist such as an ABF film is used as the resist 9, it is not necessary to remove the resist 9.

(Effects of modification 3 of the method for manufacturing a light emitting device)
(6) Modified example 3 further differs from the formation of the conductive paste 6 on the back surface 2b of the substrate 2 in the first embodiment by forming a resist 9 on the back surface 2b of the substrate 2, and removing a part of the resist 9. The resist 9 is removed to form a groove 9o, and the groove 9o from which the resist 9 has been removed is filled with conductive paste 6.
With this configuration, the conductive paste 6 and the wiring 7 can be formed on the substrate 2 with high throughput without directly discharging the conductive paste 6 onto the back surface 2b of the substrate 2 using a light exposure technology capable of high-speed processing. can do.

(Modified example 4 of manufacturing method of light emitting device)
Modification 4 will be described below with reference to FIGS. 5(a) to 5(d). Modification 4 has most of the same features as the first embodiment described above. Therefore, the configurations that are different from the first embodiment will be described below, and the description of the common configurations will be omitted as appropriate.

5(a) to 5(d) are diagrams showing the process of forming the wiring 7 in Modification 4, and show cross-sectional views of the substrate 2. FIG.
Modification 4 differs from the above-described first embodiment in that the wiring 7 is a so-called multilayer wiring.

Unlike the protective film 8 in FIG. 2(d), the protective film 8a in FIG. 5(a) has an opening 15o formed at a position corresponding to a part of the wiring 7a. The substrate 2 shown in FIG. 5A can be formed by partially printing a protective film 8a made of an insulating resin on the substrate 2 shown in FIG. 2C.

As shown in FIG. 5(b), a wiring 7e is formed on the protective film 8a of the substrate 2 shown in FIG. 5(a). A portion of the wiring 7e is filled into the opening 15o and is formed to be electrically connected to the wiring 7a. The wiring 7e can be formed by forming a conductive paste 6 (not shown in FIG. 5(b)) using the various forming methods described above and sintering the paste.

Subsequently, as shown in FIG. 5C, a protective film 8b made of insulating resin is partially printed on the wiring 7e and the protective film 8a. In this printing, an opening 16o is formed at a position corresponding to the wiring 7e.
Thereafter, as shown in FIG. 5(d), a wiring 7f is formed in the opening 16o. The wiring 7f can also be formed by forming a conductive paste 6 (not shown in FIG. 5D) using the various forming methods described above and sintering this.

The opening 15o may be formed at a corresponding position of the wiring 7b instead of the wiring 7a, or may be formed at a corresponding position of the wiring 7a and the wiring 7b.
As the protective film 8a formed between the two layers of wirings 7a, 7b and 7e, an epoxy resin with low hygroscopicity may be used to prevent deformation due to moisture absorption.
Note that although FIGS. 5(a) to 5(d) show two-layer wiring consisting of wirings 7a and 7b and wiring 7e, wiring and a protective film are further laminated on the protective film 8b. By forming this, it is also possible to form a wiring layered in three or more layers.

(Effects of modification 4 of the method for manufacturing a light emitting device)
(7) In Modification 4, in addition to the first embodiment of the light emitting device described above, the wiring 7 (7a to 7f) is formed in multiple layers with an insulating layer (protective film 8a) interposed in at least a portion thereof.
With this configuration, multilayer wiring with a high degree of freedom in wiring to the light emitting section 3 can be manufactured at low cost.

(Second embodiment of manufacturing method of light emitting device)
The second embodiment will be described below with reference to FIGS. 6 and 7. Most of the second embodiment is common to the first embodiment described above. Therefore, the configurations that are different from the first embodiment will be described below, and the description of the common configurations will be omitted as appropriate.

In the first embodiment, the wiring 7 is formed by directly forming the conductive paste 6 on the back surface 2b of the substrate 2 and sintering the formed conductive paste 6.
On the other hand, in the second embodiment, the wiring 7 and the protective film 8 are formed on the temporary substrate, and then the wiring 7 and the protective film 8 formed on the temporary substrate are attached to the back surface 2b of the substrate 2. , the wiring 7 of the substrate 2 is formed.

In the second embodiment as well, the preparation of the substrate 2 in the above-mentioned step 1 is the same as in the first embodiment, so a description thereof will be omitted.
In the second embodiment, the following steps 2A to 8A are performed instead of steps 2 to 4 in the first embodiment.

(Step 2A)
FIG. 6(a) is a diagram showing an XZ cross section of a part of the temporary substrate 20 that is bonded to the line segment A in FIG. 1(b) on the substrate 2 when bonding to the substrate 2 in step 8A.
As an example, a temporary substrate 20 made of stainless steel is prepared. Like the substrate 2, the temporary substrate 20 is a substrate having a plane extending along the XY plane, and its size in the X direction and the Y direction is approximately equal to that of the substrate 2.

(Step 3A)
As shown in FIG. 6A, a conductive paste 6h is formed on the temporary substrate 20 using the various forming methods described above. Then, the temporary substrate 20 is heated to sinter the conductive paste 6h to form the wiring 7h. The subsequent wirings 7a, 7b, 7g, and 7f are similarly formed by forming a conductive paste on the temporary substrate 20 and sintering the conductive paste.

(Step 4A)
As shown in FIG. 6(b), a protective film 8c is formed on the temporary substrate 20. The thickness of the protective film 8c is such that the upper end (the end in the +Z direction) of the wiring 7h is exposed from the protective film 8c. The protective film 8c may also be formed by printing resin, similar to the above-mentioned protective film 8a.

(Step 5A)
As shown in FIG. 6C, a wiring 7g and a wiring 7f are formed on the protective film 8c and the wiring 7h using a conductive paste (not shown).

(Step 6A)
As shown in FIG. 6(d), a protective film 8b is formed on the wiring 7g and the protective film 8c. The thickness of the protective film 8b is such that the upper end (the end in the +Z direction) of the wiring 7f is exposed from the protective film 8b. Furthermore, as shown in FIG. 6D, a wiring 7a and a wiring 7b are formed on the protective film 8b and the wiring 7f using a conductive paste (not shown).

(Step 7A)
As shown in FIG. 7(a), a protective film 8a is formed on the protective film 8b. The thickness of the protective film 8a is such that the upper ends (ends in the +Z direction) of the wirings 7a and 7b are exposed from the protective film 8a.

(Step 8A)
As shown in FIG. 7(b), the temporary substrate 20 that has been completed up to step 7A is attached to the back surface 2b of the substrate 2. When pasting on the board 2, align the wirings 7a and 7b of the temporary board 20 with the corresponding electrodes 5 on the board 2, and paste using a conductive film or conductive adhesive paste. match.

(Step 9A)
The temporary substrate 20 shown in FIG. 7B is peeled off from the substrate 2 to which the temporary substrate 20 is bonded, leaving the wirings 7a to 7f and the protective films 8a to 8c on the substrate 2. FIG. 7C shows the substrate 2 with the temporary substrate 20 removed.

The light emitting device 1 of one embodiment shown in FIG. 1 can be manufactured by the above steps 1 and 2A to 9A.
Note that in the second embodiment, the wirings 7a to 7h of the two-layer wiring are formed, but by omitting the formation of the wirings 7g, 7h and the protective film 8c, the manufacturing method is similar to the first embodiment of the above manufacturing method. , the light emitting device 1 having one layer of wiring may be manufactured.
Alternatively, the light emitting device 1 having three or more layers of wiring may be manufactured by further laminating and forming wiring and a protective film on the temporary substrate 20.

In the second embodiment, since the conductive paste 6h and the like are not sintered on the substrate 2, there is no need to heat the substrate 2 to about 200°C. Therefore, adverse effects such as thermal deformation on the substrate 2 during the manufacturing process can be prevented.

Peeling of the temporary substrate 20 is performed, for example, by mechanically peeling off the temporary substrate 20 from the wiring 7h and the protective film 8f. For this purpose, the temporary board 20 is made of a material that has weak bonding strength with the sintered conductive paste forming the wiring 7h and the resin forming the protective film 8c, and has strong mechanical strength. It is preferable. As the temporary substrate 20 that satisfies this condition, for example, a stainless steel substrate such as SUS304 (ISO 4301-304-00-I) or SUS430 (ISO 4016-430-00-I) can be used.

After the temporary substrate 20 made of stainless steel is peeled off from the substrate 2 and cleaned, it may be used again as the temporary substrate 20 for manufacturing the light emitting device 1.
Note that a copper substrate or a glass substrate may be used as the temporary substrate 20.

(Modified example 5 of manufacturing method of light emitting device)
The manufacturing method of modification 5 will be described below with reference to FIGS. 8 and 9. In modification 5, a temporary substrate 21 made of glass is used in place of the temporary substrate 20 made of stainless steel in the second embodiment described above. Further, as the substrate 2 and the temporary substrate 21, those whose sizes in the X direction and Y direction are larger than the size in the X direction and Y direction of the light emitting device 1, which is the final product, are used. However, the other manufacturing steps are generally the same as in the second embodiment described above. Therefore, the configurations that are different from the second embodiment will be described below, and the description of the common configurations will be omitted as appropriate.

(Process 2B)
FIG. 8(a) is a diagram showing an XZ cross section of a part of the temporary substrate 21 that is bonded to the line segment A in FIG. 1(b) on the substrate 2 when bonding to the substrate 2 in step 6B. However, as mentioned above, the size of the substrate 2 and the temporary substrate 21 in the X direction and the Y direction is larger than the size of the final product, the light emitting device 1. It represents an XZ cross section of a portion that is wider in the −X direction than the portion of line segment A.

As shown in FIG. 8(a), a glass temporary substrate 21 is prepared, on which a first temporary layer 22 and a second temporary layer 23 are formed in order from the temporary substrate 21 side on the +Z side surface. . Here, the second temporary layer 23 is mainly made of a metal such as copper that has high conductivity and is relatively easy to chemically etch, and the first temporary layer 22 is made of a metal such as nickel or titanium that has good adhesion to glass. The main component is a metal with a high The thickness of the temporary substrate 21 is, for example, about 1 to 1.5 mm. The thickness of the second temporary layer 23 is, for example, approximately 1 μm or less.

(Process 3B)
As shown in FIG. 8(b), a conductive paste is formed on the second temporary layer 23 on the temporary substrate 21 using the various forming methods described above, and the temporary substrate 21 is heated to become conductive. The paste is sintered to form wiring 7g.
When the second temporary layer 23 has copper as its main component, a copper paste may be used as the conductive paste. Thereby, the adhesion of the wiring 7g to the second temporary layer 23 can be improved.

(Step 4B)
Thereafter, as shown in FIG. 8C, a conductive paste is formed on a part of the wiring 7g and is sintered to form the wiring 7f. Furthermore, a protective film 8b is formed on the wiring 7g and on the temporary substrate 21. The thickness of the protective film 8b is such that the upper end (the end in the +Z direction) of the wiring 7f is exposed from the protective film 8b. The protective film 8b may also be formed by printing resin.

(Step 5B)
As shown in FIG. 8D, a wiring 7a and a wiring 7b are formed using conductive paste on the protective film 8b and the wiring 7f.
Note that a film of metal such as copper may be selectively formed on the formed wirings 7a and 7b by electroplating to increase the thickness of the wirings 7a and 7b and reduce the electrical resistance.
After that, a protective film 8a is formed on the protective film 8b. The thickness of the protective film 8a is such that the upper ends (ends in the +Z direction) of the wirings 7a and 7b are exposed from the protective film 8a.

(Step 6B)
As shown in FIG. 9(a), the temporary substrate 21, which has been completed up to step 5B, is attached to the back surface 2b of the substrate 2. When pasting on the board 2, align the wirings 7a and 7b of the temporary board 21 with the corresponding electrodes 5 on the board 2, and paste using a conductive film or conductive adhesive paste. match.

(Step 7B)
Both ends in the X direction and both ends in the Y direction of the periphery of the bonded temporary substrate 21 and substrate 2 shown in FIG. 9(a) are cut along the cutting plane DC shown by the broken line. Note that FIG. 9A shows only the cut plane DC near the ends of the temporary board 21 and the board 2 in the -X direction.
The cutting at the cutting plane DC is performed, for example, by using a dicing saw or by cutting the substrate 2 by impact such as mechanically striking the peripheral portion thereof.
By cutting at the cut plane DC, the first temporary layer 22 and the second temporary layer 23 formed on the surface of the temporary substrate 21 are exposed to the cut plane DC.

(Step 8B)
The temporary substrate 21 is peeled off from the substrate 2 to which the temporary substrate 21 is attached, with the first temporary layer 22 and the second temporary layer 23 as boundaries, leaving the wirings 7, 7f, 7g and protective films 8a, 8b on the substrate 2. do. Since the first temporary layer 22 and the second temporary layer 23 are exposed at the cut surface DC by the above-mentioned cutting, the temporary substrate 21 can be efficiently peeled off using the first temporary layer 22 and the second temporary layer 23 as peeling layers. can do.

(Step 9B)
Thereafter, the first temporary layer 22 and the second temporary layer 23 remaining on the back surface 2b side of the substrate 2 are removed by etching or the like.
FIG. 9B shows the substrate 2 with the temporary substrate 21 peeled off and the first temporary layer 22 and the second temporary layer 23 removed.
The light emitting device 1 of one embodiment shown in FIG. 1 can be manufactured by the above steps 1 and 2B to 9B.
Although the fifth modification uses a method of pasting the substrate 2 after step 5B, the light emitting sections 3 may be mounted individually instead of as a substrate 2 including a plurality of light emitting sections 3.

(Variation 6 of manufacturing method of light emitting device)
The manufacturing method of modification 6 will be described below with reference to FIG. The manufacturing process of Modified Example 6 is generally the same as that of Modified Example 5 described above, so the different configurations from Modified Example 5 will be described below, and the description of common configurations will be omitted as appropriate.

In Modified Example 6, after completing Step 3B of Modified Example 5, as shown in FIG. A conductive layer 24 whose main component is a metal such as copper, which can be relatively easily etched, is formed by plating or the like. Note that the conductive layer 24 is made of a material with a higher etching rate than the wiring 7g. Conversely, in Modification 6, the wiring 7g is made of a material with a lower etching rate than the conductive layer 24. As an example, the wiring 7g may be formed of sintered silver paste, and the conductive layer 24 may be formed of copper plating.

In Modification 6 as well, the processes from Step 4B to Step 8B described above are then performed in the same manner as in Modification 5. FIG. 10(b) shows the state of the substrate 2 after the peeling of the temporary substrate 21 in step 8B in Modification 6 has been completed. A portion of the second temporary layer 23 remains below the wiring 7g formed on the substrate 2 (-Z side) and below a portion of the conductive layer 24.

Thereafter, in the sixth modification, the above-described process 9B is performed in the same manner as in the fifth modification. The remaining second temporary layer 23 is removed by the etching process in step 9B. Furthermore, a portion of the conductive layer 24, which is made of a material with a higher etching rate than the wiring 7g, is removed using the wiring 7g as an etching mask. That is, a portion of the conductive layer 24 that is formed between the plurality of wirings 7g and makes the plurality of wirings 7g conductive to each other is removed by this etching process.

FIG. 10(c) shows the state of the substrate 2 after the process of step 9B has been completed in modification example 6. The etching process in step 9B results in a structure in which the conductive layer 24 covers the periphery of the wiring 7g except for the exposed surface of the wiring 7g. As a result, even if the wiring 7g formed by the conductive paste is thin, by patterning the conductive layer 24 using the wiring 7g as an etching mask, the wiring 7g and the conductive layer 24 are thick as a whole, that is, the electrical resistance is small. Wiring can be formed.

From another point of view, the wiring 7g formed by conductive paste can be made thinner, and as a result, the wiring 7g formed with a thinner or narrower pitch can be formed using a conductive paste with a lower viscosity. It becomes possible.
Note that the above-described film formation of the conductive layer 24 in Modification 6 and the etching using the wiring 7g as an etching mask may also be used in the manufacturing method of the second embodiment using the above-described stainless steel temporary substrate 20. .

Also in the above-described second embodiment, modification 5, and modification 6, the formation of the wirings 7a, 7b, 7f, 7g, and 7h (hereinafter also generically referred to as wiring 7A) on the temporary substrate 20 is conducted using conductive wires. The adhesive paste 6h and the like may be formed all at once on the temporary substrate 20 by screen printing or the like, or may be formed individually using a dispenser or the like.
When forming the conductive paste 6h etc. individually with a dispenser etc., the position of the electrode 5 formed on the substrate 2 to be bonded is measured, and the conductive paste 6h etc. and the wiring 7A are formed based on the measured position information. The relative positional relationship between the two may be corrected. Thereby, even if the substrate 2 is deformed, the wiring 7A can be formed in position alignment with the electrode 5 with high precision.

In the second embodiment, modification example 5, and modification example 6 described above, the resist 9 is formed on the temporary substrate 20, the resist 9 is exposed to light to form the groove portions 9o, and the conductive paste 6h or the like is applied to the groove portions 9o. The wiring 7A may be formed by filling. In this case, a laser beam scanning type exposure device is used for the groove portion 9o corresponding to a portion of the wiring 7A that requires high positional accuracy, and a fixed mask is used for the groove portion 9o corresponding to a portion that does not require high positional accuracy. Exposure may be performed using an exposure apparatus.

(Effects of the second embodiment, modification 5, and modification 6 of the method for manufacturing a light emitting device)
(8) In the second embodiment, modification example 5, and modification example 6, the plurality of light emitting parts 3 are arranged with their emission surfaces 4 facing the front surface 2f, and the plurality of light emitting parts 3 are connected to the plurality of light emitting parts 3. Prepare a substrate 2 formed such that the electrode 5 is exposed from the back surface 2b, and form a wiring 7 using a conductive paste 6 to be connected to at least a part of the electrode 5 on the back surface 2b of the substrate 2. It is equipped with things to do.
Further, a conductive paste 6h or the like is formed on the temporary substrates 20, 21, and the formed conductive paste 6h or the like is sintered to form wiring, and the wiring 7 formed on the temporary substrates 20, 21 is transferred to the substrate 2. The temporary substrate 20 is peeled off from the wiring 7 bonded to the back surface 2b of the substrate 2, and the wiring 7 is formed on the back surface 2b of the substrate 2.
With this configuration, in addition to the effects obtained in the first embodiment described above, it is possible to prevent thermal deformation of the substrate 2 during the manufacturing process, and it is possible to realize a higher definition light source device 1.

(9) Modification 6 further forms the conductive layer 24 on the temporary substrate 21 including the wiring 7g using a conductive material having an etching rate lower than that of the wiring 7g, and after the temporary substrate 21 is peeled from the wiring 7g, the wiring 7g The conductive layer 24 is etched using as a mask. With this configuration, even if the wiring 7g formed of the conductive paste is thin, the wiring 7g and the conductive layer 24 can form a wiring having a small electrical resistance as a whole. Further, the wiring 7g formed by the conductive paste can be made thinner, and thereby the wiring 7g can be formed thinner or with a narrower pitch.

(Modification 7 of manufacturing method of light emitting device)
The manufacturing method of Modification Example 7 will be described with reference to FIG. 11(a). The manufacturing process of Modification Example 7 is generally the same as that of Modification Example 6 described above, so the different configurations from Modification Example 6 will be explained below, and the description of common configurations will be omitted as appropriate.

In modification 7, the conductive layer 24 in modification 6 is formed not immediately after the wiring 7g is formed, but after the wiring 7f is formed on the wiring 7g. As a result, as shown in FIG. 11A, the conductive layer 24a covers not only the periphery of the wiring 7g except for the exposed surface of the wiring 7g, but also the periphery of the wiring 7f. With this configuration, it is possible to further increase the adhesion between the wiring 7f and the wiring 7g, and improve the strength.

(Modification 8 of manufacturing method of light emitting device)
The manufacturing method of Modification Example 8 will be described with reference to FIG. 11(b). Since the manufacturing process of Modification 8 is generally the same as that of Modification 7 described above, the different configurations from Modification 7 will be explained below, and the description of common configurations will be omitted as appropriate.

In Modification 8, after wirings 7a and 7b are formed in Modification 7, a metal layer 71 of a predetermined thickness, such as copper, is formed on wirings 7a and 7b by electrolytic plating. The thickness of the metal layer 71 is set so that the wirings 7a and 7b are not electrically connected in the XY direction. With this configuration, the electrical resistance of the wiring including the metal layer 71 and the wiring 7a or 7b can be further reduced.

Note that in Modification 8, the conductive layer 24 of Modification 6 may be formed instead of the conductive layer 24a. That is, the conductive layer 24 may be formed after forming the wiring 7g and before forming the wiring 7f on the wiring 7g.
Further, the above-described formation of the conductive layer 24a and the formation of the metal layer 71 in Modifications 7 and 8 may also be used in the manufacturing method of the second embodiment using the above-described stainless steel temporary substrate 20. .

In the light emitting device 1 and various manufacturing methods of the light emitting device 1 described above, the light emitting section 3 is not limited to the above configuration. For example, the light emitting section 3 does not need to include any one or more of the transparent substrate 11, the fluorescent layer 12, and the protective layer 13. For example, when the light emitting section 3 does not have the protective layer 13, the emission surface of the light emitting section 3 becomes the +Z side surface of the fluorescent layer 12. Similarly, the emission surface of the light emitting section 3 may be the surface on the +Z side of the member disposed closest to the +Z side among the members constituting the light emitting section 3.

The substrate 2 is not limited to the above-mentioned rectangular flat plate, but may be a flat plate of another shape or a plate-like member having a curved surface.
The shape of the emission surface 4 of the light emitting section 3 is not limited to the above-mentioned rectangle, but may be any shape such as a hexagon. Furthermore, the arrangement of the light emitting parts 3 within the substrate 2 is not limited to the above-mentioned arrangement along the X direction and the Y direction, but may be any arrangement along other directions.

Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments considered within the technical spirit of the present invention are also included within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1... Light emitting device, 2... Substrate, 2f... Front surface, 2b... Back surface, 3... Light emitting part, 4... Emission surface, 5... Electrode, 6, 6a-6d, 6h... Conductive paste, 7, 7a, 7b, 7e to 7h... Wiring, 8, 8a to 8c... Protective film, 9... Resist, 10... Light emitting element, 11... Transparent substrate, 12... Fluorescent layer, 13... Protective layer, 20, 21... Temporary substrate, 22... 1st temporary layer, 23...2nd temporary layer

Claims (14)

preparing a substrate in which a plurality of light emitting parts are arranged with their emission surfaces facing the front surface, and a plurality of electrodes connected to the plurality of light emitting parts are exposed from the back surface;
forming a wiring using conductive paste on the back surface of the substrate, the wiring being connected to at least a portion of the electrode;
Equipped with
detecting position information of the electrodes formed on the substrate;
A method of manufacturing a light emitting device , wherein at least a portion of the wiring is formed by changing a mutual positional relationship based on the positional information . The method for manufacturing a light emitting device according to claim 1 ,
Based on the position information of the electrode,
forming part of the wiring by changing the mutual positional relationship,
forming the wiring other than the part with a fixed mutual positional relationship;
A method for manufacturing a light emitting device. In the method for manufacturing a light emitting device according to claim 1 or 2 ,
forming the conductive paste on the back surface of the substrate and sintering the formed conductive paste to form the wiring on the back surface of the substrate;
A method for manufacturing a light emitting device. preparing a substrate in which a plurality of light emitting parts are arranged with their emission surfaces facing the front surface, and a plurality of electrodes connected to the plurality of light emitting parts are exposed from the back surface;
forming a wiring using conductive paste on the back surface of the substrate, the wiring being connected to at least a portion of the electrode;
Equipped with
forming the conductive paste on a temporary substrate and sintering the formed conductive paste to form wiring;
bonding the wiring formed on the temporary substrate to the back surface of the substrate;
A method for manufacturing a light emitting device, wherein the temporary substrate is peeled off from the wiring bonded to the back surface of the substrate. In the method for manufacturing a light emitting device according to claim 4 ,
A method of manufacturing a light emitting device, using a stainless steel substrate as the temporary substrate. In the method for manufacturing a light emitting device according to claim 4 ,
A method of manufacturing a light emitting device, using a glass substrate as the temporary substrate. In the method for manufacturing a light emitting device according to any one of claims 4 to 6 ,
forming a conductive layer on the temporary substrate including the wiring using a conductive material having a higher etching rate than the wiring;
A method for manufacturing a light emitting device, wherein after peeling off the temporary substrate from the wiring, the conductive layer is etched using the wiring as a mask. In the method for manufacturing a light emitting device according to any one of claims 3 to 7 ,
A method for manufacturing a light emitting device, wherein at least part of the formation of the conductive paste is performed by discharging the conductive paste using a dispenser or an inkjet head. In the method for manufacturing a light emitting device according to claim 3 ,
Forming the conductive paste on the back surface of the substrate includes:
forming a resist on the back surface of the substrate;
removing a portion of the resist to form a groove;
filling the groove portion from which the resist has been removed with the conductive paste;
A method for manufacturing a light emitting device. In the method for manufacturing a light emitting device according to any one of claims 4 to 7 ,
Forming the conductive paste on the temporary substrate includes:
forming a resist on the temporary substrate;
removing a portion of the resist to form a groove;
filling the groove portion from which the resist has been removed with the conductive paste;
A method for manufacturing a light emitting device. In the method for manufacturing a light emitting device according to any one of claims 1 to 10 ,
A method of manufacturing a light emitting device, using a substrate containing a resin material as the substrate. In the method for manufacturing a light emitting device according to any one of claims 1 to 11 ,
A method for manufacturing a light emitting device, comprising forming an insulating layer covering at least a portion of the wiring. In the method for manufacturing a light emitting device according to any one of claims 1 to 12 ,
A method for manufacturing a light emitting device, wherein the wiring is formed in multiple layers with an insulating layer interposed in at least part of the wiring. In the method for manufacturing a light emitting device according to any one of claims 1 to 13 ,
A method for manufacturing a light emitting device, wherein the thickness of the wiring is 20 μm or less.

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