JP7801577B2 - Method for manufacturing stainless steel plate and method for manufacturing light-emitting device using stainless steel plate - Google Patents

Description

This disclosure relates to a method for manufacturing a stainless steel plate and a method for manufacturing a light-emitting device using a stainless steel plate.

Patent Document 1 discloses that, as a pretreatment before applying photoresist during etching of stainless steel sheets, the oxide film on the surface of the stainless steel sheet is removed by treating it with a phosphoric acid solution or a mixed solution of phosphoric acid and nitric acid. This improves adhesion between the stainless steel sheet and the photoresist, allowing a pattern to be formed on the stainless steel sheet by etching.

JP 8-225960

We provide a method for manufacturing a stainless steel plate with an etching pattern and a method for manufacturing a light-emitting device using the stainless steel plate.

The method for manufacturing a stainless steel plate disclosed in the embodiment comprises, in this order: an application step in which at least a portion of a stainless steel plate is immersed in an aqueous solution containing at least one water-soluble polyoxyethylene alkyl ether phosphate ester or salt thereof, or the aqueous solution is sprayed onto at least a portion of the stainless steel plate; a resist formation step in which a photoresist pattern is formed on the surface of the stainless steel plate to which the aqueous solution has been applied; and an etching step in which the surface of the stainless steel plate exposed from the photoresist is etched.

The method for manufacturing a light-emitting device disclosed in the embodiment includes, in the process of manufacturing a light-emitting device using the stainless steel plate described in any one of claims 1 to 8, image recognition of the etching pattern formed in the etching process.

This disclosure provides a method for manufacturing a stainless steel plate having an etching pattern formed thereon and a method for manufacturing a light-emitting device using the stainless steel plate.

1 is a flowchart showing a method for manufacturing a stainless steel plate according to the present embodiment. 3A to 3C are cross-sectional views for explaining a method for manufacturing a stainless steel plate according to the present embodiment. FIG. 2 is a schematic diagram for explaining the action of a phosphate ester surfactant in the method for manufacturing a stainless steel plate according to the present embodiment. FIG. 2 is a top view illustrating an example of a stainless steel plate on which an etching pattern is formed in the present embodiment. FIG. 10 is a top view showing an example of a shape of a mask as viewed from above. FIG. 1 is a cross-sectional view showing an example of a light-emitting device manufactured using a stainless steel plate on which an etching pattern is formed in this embodiment. 10A to 10C are diagrams illustrating a process for manufacturing a light emitting device using a stainless steel plate on which an etching pattern is formed in this embodiment. 1 is a photograph showing a part of an area where an etching pattern is formed on the stainless steel plate of Example 1. 1 is a photograph showing a part of an area where an etching pattern was formed on the stainless steel plate of Comparative Example 1.

In this specification and claims, polygons such as triangles and quadrilaterals are referred to as polygons, including shapes in which the corners have been rounded, chamfered, corner-cut, rounded, etc. Furthermore, shapes in which processing has been applied not only to the corners (edges of the sides) but also to the middle of the sides are also referred to as polygons. In other words, shapes that have been partially processed while retaining the polygonal base are included in the interpretation of "polygon" as described in this specification and claims.

The same applies to words that describe specific shapes, such as trapezoids, circles, and irregularities, not just polygons. The same also applies when dealing with the sides that make up that shape. In other words, even if the corners or middle of a side have been modified, the interpretation of "side" includes the modified parts. Note that when distinguishing a "polygon" or "side" that has no partial modification from a modified shape, the word "strict" is added, for example, "strict quadrilateral."

In addition, in this specification or claims, terms such as up and down, left and right, front and back, front and back, front and back, front and back, etc. merely describe relative positions, orientations, directions, etc., and do not necessarily correspond to the relationships that exist during use. Furthermore, the term "top view" used in the embodiments refers to a view looking toward the surface of the stainless steel plate on which the pattern has been formed, or the surface of the stainless steel plate on which the pattern is to be formed. Therefore, the surface of the stainless steel plate on which the pattern has been formed, or the surface of the stainless steel plate on which the pattern is to be formed, is the top surface (front), and the opposite side is the bottom surface (back).

A method for manufacturing a stainless steel plate according to an embodiment of the present disclosure will be described in detail with reference to the drawings. However, the embodiments shown below are merely examples of manufacturing methods for embodying the technical concept of the present embodiment, and are not limited to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in the embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative examples. Note that the size, positional relationships, etc. of components shown in each drawing may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate the same or similar components, and detailed description will be omitted as appropriate. End views showing only the cut surface may be used as cross-sectional views.

First Embodiment
A method for manufacturing a stainless steel plate according to a first embodiment will be described with reference to Figures 1, 2(A) to 2(F), and 3. Figure 1 is a flowchart showing the method for manufacturing a stainless steel plate according to this embodiment. Figures 2(A) to 2(F) are cross-sectional views for explaining the method for manufacturing a stainless steel plate according to this embodiment. Figure 3 is a schematic diagram for explaining the effect of a phosphate ester surfactant in the method for manufacturing a stainless steel plate according to this embodiment.

As shown in Figure 1, the method for manufacturing a stainless steel plate according to this embodiment includes, in this order, a coating process S1, a resist formation process S2, and an etching process S3.

The application step S1 is a step in which at least a portion of the stainless steel plate material 10 is immersed in an aqueous solution P containing at least one water-soluble polyoxyethylene alkyl ether phosphate ester or salt thereof, or the aqueous solution P is sprayed onto at least a portion of the stainless steel plate material 10.

First, as shown in FIG. 2(A), a stainless steel plate 10 is prepared. The stainless steel plate 10 is made of a stainless steel material and has an oxide coating on at least a portion of its surface. In this embodiment, any stainless steel grade can be used as long as it is wet-etchable. For example, austenitic, austenitic-ferritic (two-phase), ferritic, or martensitic stainless steels are preferred for the stainless steel plate 10 from the standpoint of corrosion resistance to corrosive gases such as sulfide gases in the atmosphere. In particular, SUS304 or SUS316 is preferred for austenitic stainless steels, SUS329J1 for austenitic-ferritic (two-phase) stainless steels, SUS430 for ferritic stainless steels, and SUS410 for martensitic stainless steels are preferred. The thickness of the stainless steel plate 10 is, for example, 0.05 mm or more and 5.00 mm or less. The surface roughness of the stainless steel plate 10 is preferably as smooth as possible from the standpoints of adhesion to the photoresist film 20 (described below) and etching accuracy. By "smooth," it is preferable to mean a surface gloss that is at least semi-glossy or glossy, as commonly used in the silver-plated lead frame industry. The surface gloss of the stainless steel sheet material 10 preferably has a GAM value of 0.4 or higher. The GAM value is a numerical value of gloss measured, for example, with a Digital Densitmeter Model 144 manufactured by GAM (Graphic Arts Manufacturing) or a micro-surface colorimeter/reflectometer VSS7700 or densitometer (reflection density meter) ND-11 manufactured by Nippon Denshoku Industries Co., Ltd.

Before the coating step S1, the stainless steel sheet material 10 is preferably degreased to remove (clean) any oil, rust, or dirt on its surface. Degreasing methods include immersion in a hydrocarbon solvent, steam cleaning, immersion in an alkaline degreaser, or alkaline electrolytic degreasing. It is then preferable to activate the sheet by immersion in a few percent aqueous sulfuric acid or hydrochloric acid solution.

After degreasing the stainless steel plate 10, an aqueous solution P containing at least one water-soluble polyoxyethylene alkyl ether phosphate ester or salt thereof is applied to the surface of the stainless steel plate 10. The polyoxyethylene alkyl ether phosphate ester or salt thereof may be water-soluble. The water-soluble polyoxyethylene alkyl ether phosphate ester or salt thereof used in this embodiment is a phosphate ester surfactant, which belongs to the anionic surfactant category. From the viewpoints of water solubility and surfactant action, the polyoxyethylene alkyl ether phosphate ester is preferably one represented by chemical formula (a-1) or chemical formula (a-2).
[In the formula, R is 4 to 16, and n is 5 to 40.]
[In the formula, R is 4 to 16, and n is 5 to 40.]

The aqueous solution P may contain two or more polyoxyethylene alkyl ether phosphate esters or salts thereof. Furthermore, in order for the polyoxyethylene alkyl ether phosphate esters or salts thereof contained in the aqueous solution P to maintain their surfactant properties, the aqueous solution P may contain an appropriate pH buffer such as disodium phosphate or boric acid. Furthermore, in order to improve the wettability of the aqueous solution P to the stainless steel sheet material 10, the aqueous solution P may contain an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, or a polymeric surfactant other than those represented by chemical formula (a-1) or chemical formula (a-2). Examples of anionic surfactants include RCOO ^- Na ⁺ (sodium fatty acid (soap)), _ROSO3 ^- Na ⁺ ( _monoalkyl sulfate), RO( _CH2CH2O ) _mSO3 ^- Na ⁺ (alkyl _{polyoxyethylene} sulfate), _{RR'CH2CHC6H4SO3} ^- _Na ⁺ (alkyl benzene sulfonate), and _ROPO (OH)O ^- Na ⁺ (monoalkyl phosphate). Examples of nonionic surfactants include RO( _CH2CH2O ) _mH (polyoxyethylene alkyl ether), fatty acid sorbitan ester, alkyl polyglucoside, RCON( _CH2CH2OH ) ₂ (fatty _acid diethanolamide), and _ROCH2CH (OH) _CH2OH (alkyl monoglyceryl ether). Examples of amphoteric surfactants include R(CH ₃ ) ₂ NO (alkyldimethylamine oxide) and R(CH ₃ ) ₂ N ⁺ CH ₂ COO ⁻ (alkylcarboxybetaine). Examples of polymer surfactants include polyallylamine and polyoxyethylene polyoxypropylene glycol. R=8 to 16.

In the coating process, the concentration of the polyoxyethylene alkyl ether phosphate ester or its salt contained in the aqueous solution P is preferably 0.05 g/L or more and 10.00 g/L or less, and more preferably 0.1 g/L or more and 3.0 g/L or less. By setting the concentration of the polyoxyethylene alkyl ether phosphate ester or its salt to 0.05 g/L or more and 10.00 g/L or less, a film of a compound containing a water-soluble polyoxyethylene alkyl ether phosphate ester (hereinafter sometimes referred to as a water-soluble phosphate ester film) can be formed on the surface of the stainless steel sheet 10, thereby achieving strong adhesion between the stainless steel sheet 10 and the photoresist film 20. Furthermore, because the concentration of the polyoxyethylene alkyl ether phosphate ester or its salt is 10.00 g/L or less, the aqueous solution P is not wasted during rinsing with water after coating the stainless steel sheet 10, which is economical.

The aqueous solution P is applied to the stainless steel plate 10 by either immersing at least a portion of the stainless steel plate 10 in the aqueous solution P or by spraying the aqueous solution P onto at least a portion of the stainless steel plate 10. When immersing, it is preferable to agitate or circulate the treatment tank so that the aqueous solution P contacts the surface of the stainless steel plate 10 thoroughly. When spraying, it is preferable to maintain the spray nozzle structure and spray pressure so that a sufficient amount of aqueous solution P is applied to the surface of the stainless steel plate 10.

In the application step S1, the temperature of the aqueous solution P is preferably 10°C or higher and 60°C or lower. By setting the temperature of the aqueous solution P to 10°C or higher and 60°C or lower, oxidation of the surface of the stainless steel plate 10 is suppressed, making it easier for the water-soluble phosphate ester film to adhere to the stainless steel plate 10.

In the application step S1, the time for immersing the stainless steel plate 10 in the aqueous solution P or spraying the aqueous solution P onto the stainless steel plate 10 is preferably 5 to 60 seconds. By setting the treatment time to 5 to 60 seconds, the water-soluble phosphate ester film is more easily adhered to the stainless steel plate 10, and production efficiency per unit time is also good.

After the coating process S1, the stainless steel plate 10 coated with the aqueous solution P is washed with pure water and dried. A film of water-soluble phosphate ester of at least one molecular layer (several nm thick) is adhered to the surface of the washed and dried stainless steel plate 10. This is followed by the resist formation process S2, in which a photoresist 21 is patterned on the surface of the stainless steel plate 10 coated with the aqueous solution P.

In this embodiment, a process for forming a negative-type photoresist 21 is described as an example. As shown in FIG. 2(B), a liquid photoresist film 20 is applied and dried to at least a portion of the upper and lower surfaces of a stainless steel plate 10 coated with aqueous solution P, or a 15 μm-thick film-like photoresist film (in other words, a dry film) 20 is adhered by thermocompression bonding, for example, at a temperature of 110°C, a pressure of 0.3 MPa, and a roller feed speed of 1.3 m/min. Stainless steel surfaces typically have a thick, dense oxide film containing Cr with negatively charged hydroxyl groups. After the application process S1, the stainless steel plate 10 of this embodiment has a water-soluble phosphate ester film attached to the oxide film, as shown in FIG. 3. The water-soluble phosphate ester film, including anionic phosphate ester surfactants, exhibits antistatic properties similar to cationic surfactants due to the orientation of its functional groups. This electrically neutralizes the Cr oxide film, which has hydroxyl groups that are inherently negatively charged, improving adhesion to the photoresist film 20. In other words, in this embodiment, the electrostatic orientation of the surface of the stainless steel plate 10 is changed using an anionic surfactant that has a charge, thereby improving adhesion between the stainless steel plate 10 and the photoresist film 20.

Next, as shown in Figure 2(C), a mask 30 is placed on the photoresist film 20, and ultraviolet (UV) light with a wavelength of 365 nm is irradiated at an output of 60 mJ/ ^cm2 for 3 seconds. The photoresist film 20 on the stainless steel plate 10 is then treated at 24°C to 30°C with a developer solution containing, for example, 60 g/L to 100 g/L of sodium carbonate. This removes the photoresist film 20 that was not irradiated with ultraviolet light, leaving a photoresist 21 formed from the photoresist film 20 made of a liquid resist or dry film, and exposing a portion of the surface of the stainless steel plate 10, as shown in Figure 2(D).

After the photoresist film 20 is exposed and developed to form a pattern of photoresist 21, the etching process S3 is performed. The etching process S3 is a process for etching the surface of the stainless steel plate material 10 exposed from the photoresist 21.

As shown in Figure 2(E), when an etching solution is applied, for example, by spraying, to the surface of the stainless steel plate 10 that is not covered with the photoresist 21, the surface of the stainless steel plate 10 dissolves. At this time, since the photoresist 21 and the stainless steel plate 10 are in close contact with each other, the etching solution is prevented from seeping between the photoresist 21 and the stainless steel plate 10. The etching solution is, for example, a ferrous chloride solution or a cuprous chloride solution. After the etching process, as shown in Figure 2(F), the photoresist 21 is removed with an alkaline solution such as a sodium carbonate aqueous solution, thereby obtaining a stainless steel plate 11 having an etching pattern 80 in the etched area of the stainless steel plate 10 that has approximately the same shape as the mask 30.

The depth of the etching pattern 80 can be changed by adjusting the treatment time of the etching solution. For example, recesses can be formed on the surface of the stainless steel plate 10, or the stainless steel plate 10 can be penetrated. In addition, although this embodiment uses a negative type photoresist 21 in Figures 2(B) to 2(F), a positive type photoresist can also be used.

Conventionally, when etching stainless steel sheets, the adhesion between the stainless steel sheet and the photoresist is weak, making it difficult to precisely form a fine etching pattern. In the stainless steel sheet manufacturing method of this embodiment, a coating process S1 is performed to deposit a film of water-soluble phosphate ester containing an anionic surfactant with electrostatic charge on the oxide film on the surface of the stainless steel sheet 10. This changes the electrostatic orientation on the surface of the stainless steel sheet 10 and improves adhesion between the stainless steel sheet 10 and the photoresist 21 (photoresist film 20). By improving adhesion between the stainless steel sheet 10 and the photoresist 21 and preventing penetration of the etching solution, a stainless steel sheet 11 can be produced with a fine etching pattern 80 formed with precision. Furthermore, in the coating process S1, in which the stainless steel sheet 10 is treated with aqueous solution P, the stainless steel sheet 10 is barely dissolved, thereby suppressing deterioration of the appearance of the stainless steel sheet 10, such as surface roughness and discoloration.

Second Embodiment
A stainless steel plate according to the second embodiment will be described with reference to Figures 4 and 5. Figure 4 is a top view illustrating an example of a stainless steel plate on which an etching pattern according to this embodiment is formed. Figure 5 is a top view showing an example of the shape of a mask as viewed from above. Note that the same names and symbols as those in the first embodiment indicate the same or similar components, and detailed description will be omitted as appropriate. This also applies to the embodiments described below.

Figure 4 shows the top surface of a stainless steel plate 11 with multiple etching patterns 80 formed using the manufacturing method described in the first embodiment using a stainless steel plate material 10 measuring 60.0 mm in length, 90.0 mm in width, and 0.4 mm in thickness. A total of 96 etching patterns 80 are arranged on the top surface of the rectangular stainless steel plate 11, with 45 on each long side and three on each short side. The 45 etching patterns 80 arranged on the top and bottom of the long side of the rectangle are aligned at equal intervals with adjacent etching patterns 80. Similarly, the three etching patterns 80 arranged on the left and right of the short side are aligned at equal intervals with adjacent etching patterns 80. As shown in Figure 5, each etching pattern 80 was formed using a roughly cross-shaped mask with a width x of 0.1 mm and a width y of 0.5 mm in top view, and has roughly the same shape as this mask. The depth of the etching patterns 80 from the top surface of the stainless steel plate 11 is, for example, between 0.005 mm and 0.1 mm.

The shape of the etching pattern 80 when viewed from above is not limited to this, and it may be a polygon such as a triangle or a rectangle, or a circle, an ellipse, etc. In this way, a stainless steel plate 11 can be obtained in which the desired number and shape of etching patterns 80 are formed in the desired positions on the stainless steel plate material 10.

Third Embodiment
A light-emitting device fabricated using a stainless steel plate according to this embodiment and a process for fabricating the light-emitting device will be described with reference to Fig. 6 and Fig. 7(A) to Fig. 7(F). Fig. 6 is a cross-sectional view showing an example of a light-emitting device fabricated using a stainless steel plate on which an etching pattern according to this embodiment has been formed. Fig. 7(A) to Fig. 7(F) are diagrams for explaining the process for fabricating a light-emitting device using a stainless steel plate on which an etching pattern according to this embodiment has been formed.

In this embodiment, the process of manufacturing the light-emitting device 70 using the stainless steel plate 11 includes a step of image-recognizing the etching pattern 80 formed in the etching step S3. In particular, when manufacturing the light-emitting device 70, the etching pattern 80 can be used in image recognition as a mark for grasping and determining the position at which to place the components of the light-emitting device 70 in the process of placing the components on the stainless steel plate 11.

First, the structure of the light-emitting device 70 obtained by this method will be described. The light-emitting device 70 comprises a light-emitting element 63 having at least a pair of positive and negative electrodes 64, a wavelength conversion layer 61 and a light-transmitting layer 60 provided on the main light-emitting surface of the light-emitting element 63, an adhesive resin 62 that bonds the light-emitting element 63 and the wavelength conversion layer 61, and a reflective member 65 that covers at least the side surface of the light-emitting element 63 and the adhesive resin 62. The main light-emitting surface of the light-emitting device 70 is the upper surface of the light-transmitting layer 60. The electrode 64 is provided on the side opposite the main light-emitting surface of the light-emitting element 63 (in other words, on the underside of the light-emitting element 63).

First, as shown in FIG. 7(A), a UV sheet with adhesive on both the upper and lower surfaces is placed on the top surface of the stainless steel plate 11 on which the etching pattern 80 is formed, so as not to cover the etching pattern 80. Next, as shown in FIG. 7(B), a light-transmitting layer 60 containing a translucent resin is attached to the top surface of the adhesive 51, and a semi-cured sheet made of a resin containing a wavelength conversion material such as a phosphor is placed on the top surface of the light-transmitting layer 60 and cured by heating and pressurizing. Next, as shown in FIG. 7(C), grooves 52 are formed using a blade or the like to separate the wavelength conversion layer 61 into multiple regions. At this time, it is preferable to form the grooves 52 so that they do not penetrate the light-transmitting layer 60 in order to reduce stress on the light-transmitting layer 60 caused by the blade. Next, as shown in FIG. 7(D), light-emitting elements 63 including electrodes 64 are attached to each of the divided wavelength conversion layers 61 using adhesive resin 62. The light-emitting elements 63 are positioned so that the electrodes 64 are located on the opposite side of the wavelength conversion layer 61. Next, as shown in FIG. 7(E), the light-emitting element 63, including the groove 52, light-transmitting layer 60, wavelength conversion layer 61, adhesive resin 62, and electrode 64, is compression-molded to cover the reflective member 65. The reflective member 65 may entirely cover the electrode 64. In this case, grinding or other techniques are performed until a portion of the electrode 64 is exposed, enabling electrical connection between the light-emitting device 70 and the substrate on which it is mounted. Then, as shown in FIG. 7(F), the light-transmitting layer 60 and reflective member 65 are cut along the cutting lines CL located in the grooves 52 and separated from the adhesive 51. At this time, the light-emitting element 63 is transferred to a dicing sheet, and the light-transmitting layer 60 is separated from the adhesive 51. The light-emitting device 70 shown in FIG. 6 is obtained by cutting the light-emitting element 63 along the cutting lines CL from the light-transmitting layer 60 side with a dicer.

In the fabrication of the light-emitting device 70 described above, the accuracy of determining the position of the components of the light-emitting device is extremely important in each process, such as positioning the wavelength conversion layer 61, singulating the wavelength conversion layer 61, positioning the light-emitting element 63, compression molding the reflective member 65, and cutting along the planned cutting line CL. The etching pattern 80 of this embodiment has a pattern with approximately the same shape as a mask with designed dimensions, and therefore can be suitably used as a positioning marker in image recognition.

The components of the light-emitting device 70 are explained below.

(Light-emitting element 63)
The light-emitting element 63 preferably includes various semiconductors such as III-V group compound semiconductors and II-VI group compound semiconductors. As the semiconductor, nitride-based semiconductors such as _{InXAlYGa1 -X-} YN (0≦X, 0≦Y, X+Y≦1) are preferably used, and InN, _AlN , GaN, InGaN, AlGaN, InGaAlN, etc. can also be used. Furthermore, at least a pair of positive and negative electrodes 64 are preferably provided on the surface of the light-emitting element 63 opposite to the main light-emitting surface. The electrodes 64 can be made of gold, silver, tin, platinum, rhodium, titanium, aluminum, tungsten, palladium, nickel, or alloys thereof.

(Wavelength conversion layer 61)
The wavelength conversion layer 61 is a member that absorbs at least a part of the primary light emitted by the light emitting element 63 and emits secondary light having a wavelength different from that of the primary light. The wavelength conversion layer 61 contains a wavelength conversion material. Examples of wavelength conversion materials include yttrium aluminum garnet phosphors (e.g., _Y3 (Al,Ga) _5O12 :Ce), lutetium aluminum garnet phosphors (e.g., _Lu3 (Al,Ga) _{5O12 :Ce), terbium aluminum garnet phosphors (e.g., Tb3(Al,Ga)5O12 : Ce} ), β-sialon phosphors (e.g., (Si,Al) ₃ (O,N) _{4 :} Eu), α-sialon phosphors (e.g., _Mz (Si,Al) _{12 (O,N)16 (} where 0<z≦2, and M is Li, Mg, Ca, Y, and lanthanide elements excluding La and Ce)), CASN phosphors (e.g., _CaAlSiN3 Examples of materials that can be used include nitride-based phosphors such as (Sr,Ca) _AlSiN3 :Eu) or SCASN-based phosphors (e.g., (Sr,Ca) _AlSiN3 :Eu), fluoride-based phosphors such as _KSF -based phosphors ( _{e.g., K2SiF6:Mn) or MGF-based phosphors (e.g., 3.5MgO.0.5MgF2.GeO2:Mn), CCA-based phosphors (e.g., (Ca,Sr)10(PO4)6Cl2 : Eu ) , and} quantum dot phosphors. The wavelength conversion material can be one of these phosphors used alone or two or more of these phosphors used in combination.

(Transparent layer 60)
The light-transmitting layer 60 is disposed on each of the light-emitting element 63 and the wavelength conversion layer 61, and is a member that protects the light-emitting element 63 and the wavelength conversion layer 61. The base material of the light-transmitting layer 60 is, for example, a resin such as a silicone resin, an epoxy resin, a phenolic resin, a polycarbonate resin, or an acrylic resin, or glass. The base material of the light-transmitting layer 60 may contain a filler such as silicon oxide, aluminum oxide, zirconium oxide, or zinc oxide.

(Adhesive resin 62)
The adhesive resin 62 is a member that bonds the light emitting element 63 and the wavelength conversion layer 61 together and guides light from the light emitting element 63 to the wavelength conversion layer 61. The material of the adhesive resin 62 is, for example, silicone resin.

(Reflective member 65)
The reflective member 65 is a member that covers and protects the side surfaces of the light-emitting element 63, the wavelength conversion layer 61, and the light-transmitting layer 60. The reflective member 65 preferably has light reflectivity so that light from the light-emitting element 63 is extracted to the upper surface side (the wavelength conversion layer 61 side). The reflective member 65 is preferably white, and the base material of the reflective member 65 preferably contains a white pigment such as titanium oxide or magnesium oxide. Examples of the base material of the reflective member 65 include resins such as silicone resin, epoxy resin, phenol resin, polycarbonate resin, and acrylic resin, as well as modified resins thereof.

<Example>
As Example 1, a stainless steel plate 11 was produced under the following conditions.

An austenitic SUS304 stainless steel plate 10 measuring 60.0 mm in length, 90.0 mm in width and 0.2 mm in thickness was prepared.
First, an electrolytic degreaser, trade name Pakuna Erector Z-1 (manufactured by Yuken Co., Ltd.), was dissolved in water to prepare an aqueous solution with a concentration of 50 g/L. This aqueous solution was used for cathodic electrolytic degreasing at a solution temperature of 30°C and a current density ^of 5 A/dm² for 30 seconds to clean the surface of the stainless steel sheet 10. The stainless steel sheet 10 was then immersed in a 10% aqueous sulfuric acid solution at room temperature for immersion activation. An aqueous solution of polyoxyethylene lauryl ether phosphate ester (Plysurf A219B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) with a concentration of 0.1 g/L as water-soluble P was then prepared, and the stainless steel sheet 10 was immersed in the solution for 5 seconds at 25°C. The stainless steel sheet 10 was then washed with pure water and dried.

Next, a 15 μm-thick dry film (RY-3315 manufactured by Hitachi Chemical Co., Ltd.) was placed on the entire upper and lower surfaces of the stainless steel plate 10 as a photoresist film 20, and the entire upper and lower surfaces were thermocompression-bonded by sandwiching the film from above and below at a temperature of 110°C and a pressure of 0.3 MPa. A mask 30 having the pattern shown in FIG. 5 (width x: 0.1 mm, width y: 0.5 mm) was then placed on the photoresist film 20, and the film was exposed to ultraviolet light with a wavelength of 365 nm at 60 mJ/ ^cm² for 3.2 seconds. The mask 30 was then removed, and the stainless steel plate 10 was immersed in a 10 g/L aqueous sodium carbonate solution at a temperature of 28°C for 75 seconds for development, forming a pattern of photoresist 21. Further, etching was performed for 15 seconds using a 42 Baume degree ferric chloride solution at a liquid temperature of 40°C and a spray pressure of 0.25 MPa to form an etching pattern 80 having a width x of 0.1 mm, a width y of 0.5 mm, and a depth of 0.1 mm to 0.3 mm. Thereafter, the photoresist 21 was removed by treatment with a 25 g/L sodium hydroxide solution at a liquid temperature of 50°C for 30 seconds, thereby obtaining a stainless steel plate 11.

For the stainless steel plate 11 produced in Example 1, the dimensions of the etching pattern 80 were measured to confirm the difference between the design dimensions of the mask 30 and the etching pattern 80, and the quality of the adhesion between the stainless steel plate 10 and the photoresist 21 was judged based on whether image recognition was possible. Image recognition was performed using a wavelength conversion layer singulation machine, a light-emitting element die bonder, and a half-cut dicer. In each process of producing the light-emitting device 70, the etching pattern 80 was recognized when each component was mounted, and image recognition was judged to be successful if the component mounting position was as specified. If image recognition was successful, it was determined that the adhesion between the stainless steel plate 10 and the photoresist 21 was good and the etching pattern 80 was formed as designed.

Similarly, in Examples 2 to 6, stainless steel plates 11 were produced by half-etching to form an etching pattern 80 by varying the composition, liquid temperature, treatment time, and treatment method of the polyoxyethylene alkyl ether phosphate ester or its salt in aqueous solution P. Other treatment steps and conditions were the same as in Example 1. In Example 2, an aqueous solution P containing polyoxyethylene tridecyl ether phosphate ester (Prysurf A215C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) with a concentration of 1.0 g/L was used, and in Example 3, an aqueous solution P containing polyoxyethylene alkyl (C8) tridecyl ether phosphate ester (Prysurf AL12H, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) with a concentration of 0.3 g/L was used.

In Comparative Example 1, a stainless steel plate was prepared by half-etching without treatment with aqueous solution P before applying a photoresist film to the stainless steel plate, forming an etching pattern. Furthermore, in Comparative Example 2, a stainless steel plate was prepared by half-etching with a 25% aqueous solution of phosphoric acid at 40°C for 15 seconds before applying a photoresist film to the stainless steel plate, forming an etching pattern. Other processing steps were performed under the same conditions as in Example 1. For each Example and Comparative Example, the processing conditions and the difference between the mask design values and the etching pattern dimensions are shown in Table 1.

Figure 8 is a photograph showing a portion of the area where an etching pattern was formed on the stainless steel plate of Example 1. Figure 9 is a photograph showing a portion of the area where an etching pattern was formed on the stainless steel plate of Comparative Example 1. In Example 1, an etching pattern was formed with a shape roughly equivalent to the designed mask dimensions, but in Comparative Example 1, the shape of the etching pattern differed significantly from the designed mask shape. In Examples 1 to 6, the stainless steel plate was immersed in an aqueous solution P containing at least one water-soluble polyoxyethylene alkyl ether phosphate ester or its salt, or the aqueous solution P was sprayed onto the stainless steel plate. This formed a water-soluble phosphate ester film on the surface of the stainless steel plate, strengthening the adhesion between the stainless steel plate and the photoresist. There was almost no penetration of the etching solution between them, resulting in the production of a stainless steel plate with an etching pattern of the designed dimensions. On the other hand, in Comparative Example 1, the adhesion between the stainless steel plate and the photoresist was insufficient, resulting in penetration of the etching solution between the photoresist and the stainless steel plate, resulting in an etching pattern with a shape significantly different from the designed dimensions. Furthermore, in Comparative Example 2, the stainless steel plate was treated with a 25% phosphoric acid solution, which increased the surface roughness of the stainless steel plate and resulted in insufficient adhesion to the photoresist. As a result, the etching solution seeped into the gap between the stainless steel plate and the photoresist, making it impossible to form the designed etching pattern.

Next, we confirmed whether compounds containing phosphate esters adhere to the surface of stainless steel plates when they are treated with Aqueous Solution P. Test pieces measuring 50.0 mm x 50.0 mm x 0.2 mm were prepared by treating stainless steel plates under the treatment conditions described in Examples 1 to 6 and Comparative Examples 1 and 2 above, followed by rinsing and drying. These test pieces were subjected to composition analysis at an accelerating voltage of 4 kV using a scanning electron microscope equipped with an energy dispersive X-ray spectrometry (SEM-EDX: Scanning Electron Microscope-Energy Dispersive X-ray Spectrometry, Hitachi SU8230 equipped with a Horiba SDD detector). The results are shown in Table 2.

Phosphorus element from phosphate ester was detected in the stainless steel plates treated under the conditions of Examples 1 to 6, but no phosphorus element was detected in the test pieces treated under the conditions of Comparative Examples 1 and 2. This confirmed that compounds containing phosphate ester adhered to the surface of the stainless steel plate. Furthermore, by treating the stainless steel plate with Aqueous Solution P, a film of water-soluble phosphate ester or its salt was formed on the surface of the stainless steel plate, which is thought to improve adhesion between the stainless steel plate and the photoresist and inhibit penetration of the etching solution between the stainless steel plate and the photoresist during the etching process.

REFERENCE SIGNS LIST 10 Stainless steel plate material 11 Stainless steel plate 20 Photoresist film 21 Patterned photoresist 30 Mask 40 Surfactant 51 Adhesive 52 Groove 60 Light-transmitting layer 61 Wavelength conversion layer 62 Adhesive resin 63 Light-emitting element 64 Electrode 65 Reflecting member 70 Light-emitting device 80 Etching pattern CL Planned cutting line

Claims (9)

an application step of immersing at least a portion of a stainless steel plate in an aqueous solution containing at least one water-soluble polyoxyethylene alkyl ether phosphate ester or a salt thereof or spraying the aqueous solution onto at least a portion of the stainless steel plate;
a resist forming step of forming a pattern of photoresist on the surface of the stainless steel plate material to which the aqueous solution has been applied;
an etching step of etching the surface of the stainless steel plate material exposed from the photoresist;
A method for manufacturing a stainless steel plate, comprising the steps of: The method for producing a stainless steel plate according to claim 1, wherein the polyoxyethylene alkyl ether phosphate ester is represented by the following chemical formula (a-1) or chemical formula (a-2):
[In the formula, R is 4 to 16, and n is 5 to 40.]
[In the formula, R is 4 to 16, and n is 5 to 40.] 2. The method for manufacturing a stainless steel plate according to claim 1 , wherein the photoresist is a liquid resist or a dry film. 2. The method for manufacturing a stainless steel plate according to claim 1 , wherein the concentration of the aqueous solution in the coating step is 0.05 g/L or more and 10.00 g/L or less. 2. The method for manufacturing a stainless steel plate according to claim 1 , wherein the temperature of the aqueous solution in the coating step is 10°C or higher and 60°C or lower. 2. The method for manufacturing a stainless steel plate according to claim 1 , wherein in the coating step, the time for immersing the stainless steel plate in the aqueous solution or the time for spraying the aqueous solution onto the stainless steel plate is 5 seconds or more and 60 seconds or less. 2. The method for manufacturing a stainless steel plate according to claim 1 , wherein the thickness of the stainless steel plate material in the coating step is 0.05 mm or more and 5.00 mm or less. 2. The method for manufacturing a stainless steel plate according to claim 1 , wherein the stainless steel plate material is made of any one of austenitic, austenitic-ferritic, ferritic, and martensitic stainless steels. A method for manufacturing a light-emitting device using the stainless steel plate described in any one of claims 1 to 8, wherein the etching pattern formed in the etching process is image-recognized.