JP6556009B2 - Light emitting element substrate, module, and method for manufacturing light emitting element substrate - Google Patents

Description

  The present invention relates to a light emitting element substrate, a module, and a method for manufacturing a light emitting element substrate.

  In recent years, as an alternative to conventional cathode ray tube type monitors, various types of devices such as liquid crystal televisions using light-emitting elements such as LEDs as backlight sources can be used to meet the demands for lower power consumption, larger and thinner devices. The spread of LED display devices is rapidly progressing.

  In order to mount a light emitting element as a light source in these display devices, various types of light emitting element substrates each including a support substrate and a wiring portion are usually used. A laminate in which a light emitting element is mounted on these substrates (in this specification, a laminate having such a configuration is referred to as a “module”) is widely used as a light source for the various LED display devices described above. ing.

  Conventionally, a rigid substrate in which a light emitting element is mounted on a rigid substrate made of a glass epoxy plate or the like has been widely adopted as a substrate for a light emitting element. However, in recent years, LED display devices have become larger and display screens have become more diversified. In recent years, development of flexible substrates in which metal circuits are formed on flexible substrates such as resin sheets has been progressing (patents). Reference 1). A flexible substrate has higher design freedom and higher productivity than a rigid substrate, and is expected to be further spread in the future.

  However, light resistance is required for a light emitting element substrate on which the light emitting element is mounted. This is because in the case of a light emitting element substrate having low light resistance, the light emitting element substrate is deteriorated by receiving light from the light emitting element, and in some cases, a hole is generated in the light emitting element substrate. In particular, when a blue light emitting element capable of emitting blue light having a low wavelength is mounted, the influence on the light emitting element substrate is large.

  In order to solve such a problem, Patent Document 2 discloses a light-emitting element substrate that includes a light-blocking member that blocks light from the light-emitting element in an adhesive layer that bonds a metal wiring portion.

JP 2012-59867 A JP, 2015-12206, A

  When the adhesive layer that adheres the metal wiring portion is a reflective layer, the adhesive layer contains a pigment such as titanium oxide. However, when a certain amount or more of pigment is contained, the strength of the adhesive may be lowered. An object of the present invention is to provide a light-emitting element substrate having light resistance to light from a light-emitting element without reducing the strength of an adhesive layer that bonds a metal wiring part.

  As a result of intensive studies, the present inventors have found that the above problem can be solved if the content of chlorine contained in the translucent adhesive layer is specified, and the present invention has been completed. It came to do.

  (1) A flexible substrate, a metal wiring portion formed on at least one surface side of the flexible substrate via a translucent adhesive layer, and a groove portion formed between the metal wiring portions The amount of chlorine measured by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) from the surface side of the translucent adhesive layer in the groove is 1% by mass or less. Light-emitting element substrate.

  (2) The light emitting element substrate according to (1), wherein the amount of iron and / or copper measured by the scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) is 1% by mass or less.

  (3) The substrate for a light-emitting element according to (1) or (2), wherein the b value in the Lab color system measured from the surface side of the translucent adhesive layer in the groove is 10 or less.

  (4) A module in which a light emitting element is mounted on the light emitting element substrate according to any one of (1) to (3).

  (5) The module according to (4), wherein the light emitting element mounted on the light emitting element substrate is a blue light emitting element.

  (6) The module according to (4) or (5), wherein the light emitting element has an emission wavelength peak at 430 nm or more and 470 nm or less.

  (7) The underfill containing iron and / or copper adsorbent is disposed between the light-transmitting adhesive layer and the light emitting element, and any one of (4) to (6) Module described in.

  (8) The module according to (7), wherein the adsorbent is coated with a light reflecting member.

(9) Furthermore, a sealing member for sealing the light emitting element on the flexible substrate is disposed,
The module according to any one of (4) to (8), wherein the sealing member is an epoxy resin, a modified epoxy resin, a silicone resin, or a modified silicone resin.

  (10) A step of laminating a metal layer on at least one surface side of the flexible substrate via a light-transmitting adhesive layer, and cleaning the metal layer after etching to provide a space between the metal wiring portion and the metal wiring portion. And a step of forming a groove portion, wherein a chlorine amount measured by a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) from the surface side of the translucent adhesive layer of the groove portion is The manufacturing method of the board | substrate for light emitting elements which performs the said etching and washing | cleaning so that it may become 1 mass% or less.

  (11) The etching and cleaning are performed so that the amount of iron and / or copper measured by the scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) is 1% by mass or less. (9) The manufacturing method of the board | substrate for light emitting elements of description.

  The light-emitting element substrate of the present invention is a light-emitting element substrate that has light resistance to light from the light-emitting element without reducing the strength of the adhesive layer that bonds the metal wiring portion.

It is a fragmentary sectional view of the module of the present invention, and is a mimetic diagram used for explanation of a mounting mode of a light emitting element in the module of the present invention. It is a perspective view which shows typically the outline of the layer structure of the image display apparatus which uses the module of this invention. It is a spectrum figure of a scanning electron microscope-energy dispersive X ray spectroscopy (SEM-EDX) from the surface side of the translucent adhesive layer in the light emitting element use substrate of an example. It is a spectrum figure of a scanning electron microscope-energy dispersive X ray spectroscopy (SEM-EDX) from the surface side of a translucent adhesion layer in a substrate for light emitting elements of a comparative example. It is a fragmentary sectional view of the module of other embodiments of the present invention.

  Hereinafter, each embodiment of the board | substrate for light emitting elements of this invention and a module is demonstrated. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention.

<Light emitting element substrate>
An embodiment of a light emitting element substrate of the present invention will be described. As shown in FIG. 1, the light emitting element substrate of the present embodiment on which the light emitting element 2 can be mounted has a conductive metal wiring portion 13 made of a metal layer or the like on the surface of the flexible substrate 11. It is formed via the photoadhesive layer 12. The light emitting element 2 can be provided on the metal wiring. Further, as shown in FIG. 1, a surface reflection layer 16 may be laminated around the periphery. When providing a surface reflective layer, it may be laminated on the substrate via an adhesive layer or the like on the surface of the substrate. The surface reflection layer is not an essential constituent element of the present invention.

  When providing a surface reflective layer, it is preferable that the reflectance in wavelength 450nm is 80% or more. For example, a thermosetting resin containing 10% by mass or more and 80% by mass or less of a white pigment such as titanium oxide can be used. In addition, it is more preferable that a titanium oxide is 30 to 80 mass%. Titanium oxide is most preferable from the viewpoint of the difference in refractive index, but instead of titanium oxide, or together with titanium oxide, aluminum oxide, silicon oxide, titanium oxide, magnesium oxide, antimony oxide, aluminum hydroxide, barium sulfate. At least one selected from magnesium carbonate, barium carbonate, and glass filler may be used. Examples of the thermosetting resin include a mixture of a fluororesin and an acrylic resin, a silicone resin, and an epoxy resin. From the viewpoint of adhesion to the translucent adhesive layer, a mixture of a fluororesin and an acrylic resin is preferable. The thermosetting resin is preferably hard.

[Flexible substrate]
The flexible substrate is not particularly limited, but a thermoplastic resin is preferably used. The material for the flexible substrate is required to have high heat resistance and insulation. As such a resin, polyimide resin (PI) or polyethylene naphthalate (PEN) which is excellent in heat resistance, dimensional stability during heating, mechanical strength, and durability can be used. Among them, polyethylene naphthalate (PEN) that has been improved in heat resistance and dimensional stability by performing heat resistance improvement treatment such as annealing treatment can be preferably used. In addition, polyethylene terephthalate (PET) whose flame retardancy is improved by adding a flame retardant inorganic filler or the like can also be selected as a material resin for the flexible substrate.

  It is preferable to use a flexible substrate having a thermal shrinkage start temperature of 100 ° C. or higher, or a substrate having improved heat resistance so that the temperature becomes 100 ° C. or higher by the above-described annealing treatment or the like. The peripheral portion of the element reaches a temperature of about 90 ° C. by heat generated from the normal light emitting element. From this viewpoint, it is preferable that the thermoplastic resin forming the substrate resin has heat resistance equal to or higher than the above temperature.

The light emitting element substrate is required to be a resin having an insulating property that can provide the insulating property required for the light emitting element substrate when the LED display device is integrated as a backlight or the like. In general, the substrate has a volume resistivity of preferably 10 ¹⁴ Ω · cm or more, and more preferably 10 ¹⁸ Ω · cm or more. The volume resistivity can be measured by using, for example, a digital ultra high resistance / microammeter 5450/5451 manufactured by ADC.

  The thickness of the flexible substrate is not particularly limited, but in the case of a flexible resin substrate, it is approximately 10 μm or more and 100 μm or less from the viewpoint of the balance between heat resistance and insulation and manufacturing cost. Preferably there is. Also, the thickness is preferably within the above-mentioned thickness range from the viewpoint of maintaining good productivity when manufacturing by the roll-to-roll method.

[Translucent adhesive layer]
The translucent adhesive layer according to this embodiment has a chlorine content of less than 1% by mass. Moreover, it is preferable that the amount of iron and / or copper is 1 mass% or less. Specifically, chlorine measured by a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) from the surface side of the translucent adhesive layer 12 in the groove portion 17 formed between the metal wiring portions 13. The amount and / or the amount of iron or copper is less than 1% by mass. As shown in FIG. 1, the groove portion 17 is a surface where the metal wiring portion is not laminated and the translucent adhesive layer is exposed, and refers to the surface of the translucent adhesive layer. When manufacturing the metal wiring part 13, it is common to manufacture by forming a pattern by etching the metal layer manufactured through the translucent adhesive layer between the flexible substrate and the metal layer. . Therefore, the amount of chlorine and / or the amount of iron or copper as etching residues may be contained in the translucent adhesive layer. The substrate for a light emitting device of the present invention is mainly blue by making the content of chlorine and / or iron or copper contained in the translucent adhesive layer constituting the substrate for light emitting device less than 1% by mass. Light resistance to light from the light emitting element is improved. The blue light emitting element means a light emitting element capable of emitting blue light having a wavelength of 430 nm to 500 nm. In addition, it is more preferable that the content of chlorine and / or iron or copper contained in the translucent adhesive layer constituting the light emitting element substrate is less than 0.7% by mass. Note that the substrate for a light-emitting element in which the content of chlorine and / or iron or copper contained in the translucent adhesive layer is less than 1% by mass is an etching solution concentration such as temperature and hydrochloric acid concentration as etching conditions in the etching process. It can be obtained by appropriately adjusting the etching time and the like.

  In the present invention, the method of measuring the chlorine amount and / or the iron amount or the copper amount from the surface side of the light-transmitting adhesive layer in the groove portion by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), In accordance with the quantitative conditions unique to the SEM-EDX analyzer (for example, JEM SEM “JSM-6700F” and Oxford Instruments EDX “XMAX80” acceleration voltage 15 kV, focal length 15 mm, sample tilt 0 degree) And the measurement time is adjusted so that the target element can be sufficiently detected, and characteristic X-ray spectra are acquired. The concentration of each element is determined by the ZAF correction method (atomic number correction Z, absorption correction A, fluorescence correction for the relative intensity of each element) The amount of chlorine and / or the amount of iron or copper can be determined by the method of determining the content of each element by applying F). It is also possible to determine the chlorine content, iron content, and copper content from the cross-sectional side.

  The reason why the light resistance is lowered and the flexible substrate is perforated by the amount of chlorine and / or the amount of iron or copper contained in the translucent adhesive layer is not necessarily clear. However, the translucent adhesive layer may turn yellow when the etching residue is soaked into the translucent adhesive layer by a certain amount or more. When the translucent adhesive layer is yellowed, the light absorption amount of blue light having a wavelength of about 430 nm to about 500 nm is increased in the translucent adhesive layer. And the energy of the light absorbed by the translucent adhesive layer is converted into thermal energy, and the translucent adhesive layer generates heat. It is presumed that when the light-transmitting adhesive layer generates heat, a hole is formed in the light-transmitting adhesive layer, and a hole is also formed in the flexible substrate laminated.

  The b value in the Lab color system measured from the surface side of the translucent adhesive layer in the groove is preferably 10 or less, and more preferably 5 or less. When the b value in the Lab color system is 10 or less, absorption of blue light to the translucent adhesive layer due to yellowing of the translucent adhesive layer can be suppressed. In addition, b value can be measured using KONICA MINOLTA spectrocolorimeter CM-700d according to conditions of D65 light source and 10 degree viewing angle according to JIS Z8722.

  As the adhesive forming the light-transmitting adhesive layer 12, a known resin adhesive can be used as appropriate. Of these resin adhesives, urethane-based, polycarbonate-based, or epoxy-based adhesives can be particularly preferably used. The translucent adhesive layer means an adhesive layer that transmits 85% or more of the total visible light. The translucent adhesive layer 12 can also contain a light reflecting member in the translucent resin. Thereby, the arrival of light to the flexible substrate can be reduced. Examples of the light reflecting member include white pigments such as titanium oxide.

  The surface roughness Rz (10-point average roughness defined in JIS B0601) of the translucent adhesive layer in the groove portion 17 is preferably 0.1 μm or more and 10 μm or less, and is 0.1 μm or more and 1 μm or less. Is more preferable. When the surface roughness Rz of the translucent adhesive layer in the groove part 17 is 0.1 μm or more, the adhesive strength at the interface between the metal wiring part and the translucent adhesive layer can be improved. When the surface roughness Rz is 10 μm or less, no etching residue remains in the recesses or the like on the surface of the translucent adhesive layer in the groove 17. Therefore, it is possible to prevent the flexible substrate 11 from having a hole due to an increase in the amount of light absorbed from the light emitting element in the translucent adhesive layer 12 due to the etching residue.

  In order to make the surface roughness Rz (ten-point average roughness defined by JIS B0601) of the translucent adhesive layer in the groove portion 17 to be 0.1 μm or more and 10 μm or less, a metal foil used for laminating metal layers is used. It is preferable to laminate so that the surface of the side that is sometimes in close contact with the rotating drum is in intimate contact with the translucent adhesive layer. Since the surface close to the rotating drum side is a glossy surface having a very small surface roughness, the surface roughness Rz of the translucent adhesive layer can be reduced accordingly, and flexibility It is possible to prevent the substrate 11 from having a hole. Of course, a copper foil having a surface treatment applied to a rolled copper foil, an electrolytic copper foil or the like and having an Rz of 0.1 μm or more and 10 μm or less can also be used.

[Metal wiring section]
The metal wiring part 13 is a wiring pattern formed on the surface of the light emitting element substrate 1 by a conductive base material such as a metal layer.

  The arrangement of the metal wiring part 13 is not limited to a specific arrangement as long as the light emitting element can be mounted. However, in the light emitting element substrate, it is preferable that at least 80% or more, preferably 90% or more preferably 95% or more of one surface of the substrate is covered with the metal wiring portion 13. Thereby, it can contribute to the improvement of the heat dissipation calculated | required in the module using the metal wiring part 13 and the board | substrate for light emitting elements.

200 W / (m · K) or more is preferable, and 300 W / (m · K) or more is more preferable as the thermal conductivity λ of the metal constituting the metal wiring portion 13. The metal resistivity R constituting the metal wiring part 13 is preferably 3.00 × 10 ⁻⁸ Ω · m or less, more preferably 2.50 × 10 ⁻⁸ Ω · m or less. Here, the measurement of the thermal conductivity λ can use, for example, a thermal conductivity meter QTM-500 manufactured by Kyoto Electronics Industry Co., Ltd., and the measurement of the electrical resistivity R can be performed, for example, a 6517B type electrometer manufactured by Keithley. Can be used. According to this, for example, in the case of copper, the thermal conductivity λ is 403 W / (m · K), and the electrical resistivity R is 1.55 × 10 ⁻⁸ Ω · m. Thereby, both heat dissipation and electrical conductivity can be achieved. More specifically, since the heat dissipation from the light emitting element 2 is stabilized and an increase in electrical resistance can be prevented, the variation in light emission between the light emitting elements is reduced, and the light emitting elements can stably emit light. Life is extended. Further, since deterioration of peripheral members such as a substrate due to heat can be prevented, the product life of the image display device itself incorporating the light emitting element substrate 1 as a backlight can be extended.

  The surface resistance value of the metal wiring portion 13 is preferably 500Ω / □ or less, more preferably 300Ω / □ or less, further preferably 100Ω / □ or less, and particularly preferably 50Ω / □ or less. The lower limit is about 0.005Ω / □.

  As a metal used as a material of the metal wiring part 13, metal layers, such as aluminum, gold | metal | money, silver, copper, and those alloy layers can be illustrated. The thickness of the metal wiring portion 13 may be set as appropriate according to the magnitude of the current resistance required for the light emitting element substrate, and is not particularly limited. Examples thereof include a thickness of 10 μm to 50 μm. From the viewpoint of improving heat dissipation, the thickness of the metal wiring portion 13 is preferably 10 μm or more. Further, if the metal layer thickness is less than the lower limit, the influence of thermal contraction of the substrate is large, and the warp after the treatment is likely to increase during the solder reflow process. From this viewpoint, the thickness of the metal wiring portion 13 is 10 μm. The above is preferable. When the thickness is 50 μm or less, sufficient flexibility can be maintained, and a decrease in handling property due to an increase in weight can be prevented.

[Solder layer]
In the light emitting element substrate, the metal wiring part 13 and the light emitting element 2 are preferably bonded via the solder layer 14. This joining by soldering can be performed by, for example, a reflow method or a laser method.

[Insulating protective film]
The insulating protective film 15 is not an essential constituent element in the present invention, but when the insulating protective film is provided, the metal wiring is formed by thermosetting ink, UV curable ink, or coverlay film as described above. It is formed mainly for improving the migration resistance of the light emitting element substrate in the other portions except the part where the electrical connection on the surface of the portion 13 and the light emitting element substrate is required.

  As the thermosetting ink, a known ink can be suitably used as long as the thermosetting temperature is about 100 ° C. or less. Specifically, as a representative example of an ink that can preferably use an insulating ink having a polyester resin, an epoxy resin, an epoxy resin and a phenol resin, an epoxy acrylate resin, a silicone resin, or the like as a base resin, respectively. Can be mentioned. Of these, polyester-based thermosetting insulating ink is particularly preferable as a material for forming the insulating protective film 15 of the light emitting element substrate 1 because of its excellent flexibility.

  The thermosetting ink for forming the insulating protective film 15 may be a white ink further containing an inorganic white pigment such as titanium dioxide. By whitening the insulating protective film 15, it is possible to improve the reflectance and design of the light emitting device.

  The formation of the insulating protective film 15 using the above insulating thermosetting ink can be performed by a known method such as screen printing.

  When using a coverlay film, it can be formed by applying an adhesive to a highly heat-resistant resin film such as a polyimide resin and affixing on the flexible substrate 11.

[Surface reflection layer]
The surface reflection layer 16 is not an essential constituent element in the present invention. However, in the case where the surface reflection layer is provided, in the present embodiment, the light emitting element is used in the module 10 for the purpose of improving the light emission capability. The light emitting element 2 is laminated on the outermost surface on the light emitting surface side except for the mounting portion of the light emitting element 2. It is not particularly limited as long as it is a member having a reflecting surface for reflecting the light emitted from the light emitting element and guiding it in a predetermined direction, but white polyester foam type white polyester, white polyethylene resin, silver deposited polyester, etc. And can be used as appropriate according to the required specifications.

[Light emitting element]
The light emitting element 2 is disposed on the light emitting element substrate. The light emitting element 2 has a pair of electrodes on one surface, and is electrically connected to the metal wiring portion 13 through the pair of electrodes. The light emitting element 2 used here is not particularly limited in shape or size. A light emitting color of the light emitting element 2 can be selected depending on the application, but a light emitting element that emits blue light can be used. The blue light emitting element means a light emitting element capable of emitting light having a wavelength of 430 nm to 500 nm. For example, it is preferable to use a blue light emitting element having a light emission wavelength peak at 430 nm to 470 nm. As the light emitting element 2, a GaN system or an InGaN system can be used. The _{InGaN-based, In X Al Y Ga 1-} X-Y N (0 ≦ X ≦ 1,0 ≦ Y ≦ 1, X + Y <1) , or the like can be used.

[Underfill]
FIG. 5 is a partial cross-sectional view of a module according to another embodiment of the present invention. An underfill 21 may be disposed between the light-transmitting adhesive layer 12 and the light emitting element 2 as in the module of the embodiment of FIG. The underfill 21 can increase the bonding strength between the light emitting element 2 and the translucent adhesive layer 12. The underfill 21 is preferably a thermosetting resin such as an epoxy resin or a silicone resin. The underfill 21 is preferably made of a material that enhances the bonding strength with the translucent adhesive layer 12, and the underfill 21 and the translucent adhesive layer 12 are preferably made of the same material, but are different materials. Also good.

  The underfill 21 preferably contains an adsorbent 22 that adsorbs iron and / or copper. As an adsorbent for iron and / or copper, a chelate resin or synthetic zeolite can be applied. Thereby, the penetration | invasion of the iron and / or copper to the translucent adhesive layer 12 can be prevented. The underfill 21 preferably contains a light reflecting member made of a white pigment such as titanium oxide. Thereby, the light from the light emitting element 2 can be efficiently emitted to the outside. In particular, the surface of the adsorbent 22 is preferably coated with titanium oxide. This is because the light emitted from the light emitting element 2 can be prevented from being absorbed by the adsorbent 22 and can have a high light reflectance. The light reflecting member is preferably titanium oxide, but instead of or together with titanium oxide, aluminum oxide, silicon oxide, titanium oxide, magnesium oxide, antimony oxide, aluminum hydroxide, barium sulfate, magnesium carbonate, carbonic acid At least one pigment selected from barium and glass filler may be used.

[Sealing member]
A sealing member 19 that seals the light emitting element 2 is preferably disposed on the flexible substrate 11. This is because the light emitting element 2 can be protected from dust and moisture. The sealing member 19 is preferably one of an epoxy resin, a modified epoxy resin, a silicone resin, and a modified silicone resin.

[Phosphor]
The sealing member 19 may contain the phosphor 20. The phosphor 20 absorbs light from the light emitting element 2 and emits light of different wavelengths, and emits light of green, yellow, red, and the like. As the phosphor 20, an oxide phosphor such as YAG or silicate, a nitride phosphor such as CASN or SCASN, a fluoride phosphor such as KSF, or the like can be used.

<Method for manufacturing substrate for light emitting element>
The substrate for a light emitting element is not particularly limited, and can be manufactured by a conventionally known method for manufacturing an electronic substrate. For example, it can be manufactured through the etching process described below. Further, it is preferable to subject the resin in advance to a heat resistance improving process by annealing according to the material resin to be selected.

[Annealing treatment]
Although not essential in the present invention, conventionally known heat treatment means can be used when annealing is performed. As an example of the annealing treatment temperature, when the resin substrate is PEN, it is in the range of the glass transition temperature to the melting point, more specifically in the range of 160 ° C. to 260 ° C., more preferably 180 ° C. to 230 ° C. An example of the annealing time is about 10 seconds to 5 minutes. According to such heat treatment conditions, the thermal contraction start temperature of PEN, which is generally about 80 ° C., can be improved to about 100 ° C.

[Etching process]
By stacking the metal wiring part 13 of the metal layer used as the material of the metal wiring part on the surface of the resin substrate that has undergone the annealing treatment, a laminated body that uses the material of the light emitting element substrate can be obtained. As a lamination method, a metal layer is laminated on at least one surface side of a flexible substrate via a light-transmitting adhesive layer, or a plating method or a vapor deposition method is directly applied to the surface of the flexible substrate. Examples thereof include a method of depositing the metal wiring portion 13 by sputtering, ion plating, electron beam deposition, vacuum deposition, chemical vapor deposition, or the like. From the viewpoint of cost and productivity, a method of bonding the metal layer to the surface of the flexible substrate with a urethane adhesive is advantageous.

  Next, an etching mask patterned in the shape of the metal wiring portion 13 is formed on the surface of the metal layer of the laminate. In the future, the etching mask is provided so that the wiring pattern forming portion of the metal layer to be the metal wiring portion 13 is free from corrosion by the etching solution. The method for forming the etching mask is not particularly limited. For example, when using a photoresist or a dry film, the etching mask may be formed on the surface of the laminated sheet by developing after exposure through the photomask, An etching mask may be formed on the surface of the laminated sheet by a printing technique such as an inkjet printer.

  Next, the metal layer in a portion that is not covered with the etching mask is removed with an immersion liquid. Thereby, a metal wiring part and the groove part between the said metal wiring parts can be formed. Finally, the etching mask is removed using an alkaline stripping solution. As a result, the etching mask is removed from the surface of the metal wiring portion 13.

  Etching from the surface side of the translucent adhesive layer so that the amount of chlorine and / or the amount of iron or copper measured by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) is less than 1% by mass And washing. In cleaning, the amount of chlorine and / or the amount of iron or copper can be stably reduced by adding a surfactant and using an ultrasonic cleaner. A light-emitting element substrate having light resistance can be manufactured.

[Insulating protective film and surface reflection layer forming step]
After the formation of the metal wiring portion, an insulating protective film 114 and a surface reflection layer 16 are further laminated as necessary. These laminations can be performed by a known method. Depending on the material to be employed, various laminating methods such as screen printing, dry lamination, thermal lamination, and the like can be used.

<Module>
The module 10 can be obtained by mounting the light emitting element 2 on the light emitting element substrate 1 described above. The module 10 can be used as a backlight of the LED image display device 100 as shown in FIG.

  A method for manufacturing the module 10 using the light emitting element substrate 1 will be described. Bonding of the light emitting element 2 to the metal wiring portion 13 can be preferably performed by soldering. This solder bonding can be performed by a reflow method or a laser method. In the reflow method, the light emitting element 2 is mounted on the metal wiring part 13 via solder, and then the light emitting element substrate is transported into the reflow furnace, and hot air of a predetermined temperature is blown to the metal wiring part 13 in the reflow furnace. In this method, the solder paste is melted to attach the light emitting element 2 to the metal wiring portion 13. The laser method is a technique in which solder is locally heated by a laser to solder the light emitting element 2 to the metal wiring portion 13. The solder material may be Sn-Bi-based, Sn-Cu-based, Sn-Ag-Cu-based solder or the like in accordance with the heat resistance of the flexible substrate.

  When performing solder bonding of the light emitting element 2 to the metal wiring part 13, it is preferable to use a method of performing solder reflow by laser irradiation from the back side of the light emitting element substrate. Thereby, it becomes possible to more reliably suppress the ignition of the organic component of the solder due to heating and the accompanying damage to the base material.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

<Creation of light emitting element substrate>
Example 1
As an example of the LED display device of the present invention, a metal wiring portion made of an electrolytic copper layer (thickness 35 μm) is etched on the surface of a film-like support substrate having a size of 400 mm × 500 mm (the electrolytic copper layer mat surface is flexible) The test sample of the light emitting element substrate was prepared. The etching process was performed using an etching solution (iron chloride) having a hydrochloric acid concentration of 2.6 g / L under the conditions of a temperature of 60 ° C. and an etching time of 90 seconds. As the flexible substrate, 75 μm thick polyethylene naphthalate (PEN) was used.
As an adhesive for bonding the copper foil constituting the metal wiring part to the flexible substrate, a urethane-based adhesive (“KTEP”, manufactured by Rock Paint) was used.

(Comparative Example 1)
The test of the substrate for a light emitting element was conducted in the same manner as in Example 1 except that the etching process was performed using an etching solution (iron chloride) having a hydrochloric acid concentration of 15 g / L at a temperature of 60 ° C. and an etching time of 120 seconds. Samples were manufactured.

(Example 2)
As an example of the LED display device of the present invention, a metal wiring portion made of an electrolytic copper layer (thickness 35 μm) is etched on the surface of a film-like support substrate having a size of 400 mm × 500 mm (the electrolytic copper layer mat surface is flexible) The test sample of the light emitting element substrate was prepared. The etching process was performed using an etching solution (copper chloride) having a hydrochloric acid concentration of 2.6 g / L under the conditions of a temperature of 60 ° C. and an etching time of 150 seconds. As the flexible substrate, 75 μm thick polyethylene naphthalate (PEN) was used.

  As an adhesive for bonding the copper foil constituting the metal wiring part to the flexible substrate, a urethane-based adhesive (“KTEP”, manufactured by Rock Paint) was used.

(Comparative Example 2)
A test of a substrate for a light emitting element was conducted in the same manner as in Example 2 except that the etching treatment was performed using an etching solution (copper chloride) having a hydrochloric acid concentration of 15 g / L at a temperature of 60 ° C. and an etching time of 180 seconds. Samples were manufactured.

<Measurement of chlorine, iron and copper>
The amount of chlorine, the amount of iron, and the amount of copper of the light emitting element substrates of Examples and Comparative Examples were measured. Specifically, from the surface side of the translucent adhesive layer in the groove formed between the metal wiring parts, the spectrum is obtained by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), and the chlorine content The amount of iron and the amount of copper were measured. In SEM-EDX, JEM JSM-6700F was used for SEM, and XMAX80 manufactured by Oxford Instruments was used for EDX. As a pretreatment, a Pt—Pd sputtered film was applied to several nm, the acceleration voltage was 15 kV, the focal length was 15 mm, the sample tilt was 0 degree, the emission current was 20 μA, the measurement time was 60 seconds, and the measurement magnification was 500 times. The ZAF correction method is used for quantitative analysis. 3 and 4 show spectrum diagrams of the light-emitting element substrates of Examples and Comparative Examples. In this drawing, the examples and comparative examples differ in the amounts of Fe, Cl, and Cu.

<Light resistance test>
For the light-emitting element substrates of Examples and Comparative Examples, as an accelerated test of the light resistance test, a blue laser (a laser diode manufactured by Nichia Chemical Co., Ltd., wavelength 450 nm, output 0.5 W) was irradiated from above the translucent adhesive layer in the groove. The time when the film was perforated was measured. The measurement results are shown in Table 1 below.

<Wiring adhesion test>
About each light emitting element substrate of an Example and a comparative example, the adhesive strength in the following test conditions was measured and metal adhesiveness was evaluated.
In the above metal adhesion evaluation sample, the metal wiring portion in close contact with the flexible substrate was subjected to vertical peeling (50 mm / min) with a peeling tester (Tensilon Universal Tester RTF-1150-H). ) Tests are performed and the measurement results are shown in Table 1.

(In Table 1, the transmittance means the transmittance of light having a wavelength of 380 nm or more and 780 nm or less.)

  From Table 1, the light emitting element substrate of Examples 1 and 2 in which the amount of chlorine contained in the translucent adhesive layer is 1% by mass or less is compared with Comparative Examples 1 and 2 in which the amount of chlorine exceeds 1% by mass. The time required to perforate is longer. For this reason, the light-emitting element substrate of the present invention in which the amount of chlorine contained in the light-transmitting adhesive layer is 1% by mass or less is a light-emitting element substrate having high wiring adhesion and light resistance to light from the light-emitting element. I understand that there is.

DESCRIPTION OF SYMBOLS 1 Light emitting element substrate 11 Flexible substrate 12 Translucent adhesive layer 13 Metal wiring part 14 Solder layer 15 Insulating protective film 16 Surface reflective layer 17 Groove part 10 Module 2 Light emitting element 3 Display screen 4 Heat radiation part 19 Sealing member 20 Phosphor 21 Underfill 22 Adsorbent 100 LED image display device

Claims (7)

A module in which a light emitting element is mounted on a light emitting element substrate,
The light emitting element substrate is formed between a flexible substrate, a metal wiring portion formed on at least one surface of the flexible substrate via a light-transmitting adhesive layer, and the metal wiring portion. And having a groove portion,
From the surface side of the transparent adhesive layer in the groove, scanning electron microscope - What energy dispersive X-ray spectroscopy amount of chlorine measured by (SEM-EDX) is 1 wt% or less der
A module in which an underfill containing iron and / or copper adsorbent is disposed between the light-transmitting adhesive layer and the light emitting element . From the surface side of the translucent adhesive layer in the groove, the amount of iron and / or copper measured by the scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) is 1% by mass or less. The module according to claim 1. The module of Claim 1 or 2 whose b value in a Lab color system measured from the surface side of the said translucent adhesive layer in the said groove part is 10 or less. The module according to claim 3 , wherein the light emitting element mounted on the light emitting element substrate is a blue light emitting element. The light emitting element has a peak emission wavelength below 470nm or 430 nm, the module according to claim 3 or 4. The module according to any one of claims 1 to 5, wherein the adsorbent is coated with a light reflecting member. Furthermore, a sealing member for sealing the light emitting element on the flexible substrate is disposed,
The module according to any one of claims 1 to 6 , wherein the sealing member is an epoxy resin, a modified epoxy resin, a silicone resin, or a modified silicone resin.