Metal light-shielding substrate, metal light-shielding plate, camera module, electronic device, and manufacturing method of metal light-shielding plate.

Abstract

The three-dimensional surface roughness Sa of the surface 10MR of the metal light-shielding substrate 10M used in the metal light-shielding plate is 0.142 μm or more at 50x magnification. The three-dimensional surface roughness Sz of the surface 10MR is 2.666 μm or more at 50x magnification.

Description

Technical Field

[0001] The present invention relates to a metal light-shielding plate substrate, a metal light-shielding plate, a camera module, an electronic device, and a method for manufacturing a metal light-shielding plate. This application claims the priority of Japanese Patent Application No. 2023-120877 filed on July 25, 2023, and incorporates its content herein by reference. Prior Art

[0002] A camera module included in an electronic device such as a smartphone uses a light-shielding plate member that functions as an aperture for external light. The light-shielding plate has through-holes that penetrate in the thickness direction of the plate and allow only necessary external light to pass through. The light-shielding plate suppresses image defects such as ghosting or flare in the image caused by unnecessary external light (e.g., scattered light) entering the lens and the imaging element (image sensors such as CCDs and CMOSs).

[0003] Japanese Patent Application Laid-Open No. 2021-113920 discloses a metal light-shielding plate (metal light-shielding plate) that has desired light-shielding performance even when formed thin. When manufacturing the metal light-shielding plate, through-holes are formed in a metal light-shielding plate substrate (metal foil).

[0004] When forming through-holes in the metal light-shielding plate substrate, resist layers are provided on both surfaces of the metal light-shielding plate substrate, patterns corresponding to the through-holes are formed in each resist layer, and the metal light-shielding plate substrate is etched from both surfaces using the resist layer having the pattern as a mask. Thereby, through-holes can be formed in the metal light-shielding plate substrate. Summary of the Invention

[0005] [Problems to be Solved by the Invention]

[0006] When forming through-holes in a metal light-shielding plate substrate by simply using a resist layer without any countermeasures, there are problems such as unevenness occurring at the edges of the through-holes and a large deviation in the size (e.g., diameter size) of the through-holes. At this time, unnecessary external light enters the lens and the imaging element in the camera module, and there is a problem that the light-shielding performance of the light-shielding plate cannot be ensured.

[0007] An object of the present invention is to provide a metal light-shielding plate substrate, a metal light-shielding plate, a camera module, an electronic device, and a method for manufacturing a metal light-shielding plate that can ensure the light-shielding performance of the metal light-shielding plate. [Means for Solving the Problems]

[0008] The first aspect of the present invention is a metal light-shielding plate substrate, which is used as a substrate for a metal light-shielding plate. The three-dimensional surface roughness Sa of the surface of the substrate is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the surface is 2.666 μm or more under a 50-fold field of view.

[0009] The second aspect of the present invention is a metal light-shielding plate using the metal light-shielding plate substrate of the first aspect.

[0010] The third aspect of the present invention is a camera module using the metal light-shielding plate of the second aspect.

[0011] The fourth aspect of the present invention is an electronic device using the camera module of the third aspect.

[0012] The fifth aspect of the present invention is a method for manufacturing a metal light-shielding plate, which includes the following: Prepare a metal light-shielding plate substrate, which has a surface. The surface is configured to attach a dry film resist, and openings are formed by etching using the patterned dry film resist. The three-dimensional surface roughness Sa of the surface is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the surface is 2.666 μm or more under a 50-fold field of view; Dispose the dry film resist on the surface; Form a through hole in the dry film resist. The through hole is used to form a concave portion in the metal light-shielding plate substrate. The concave portion is recessed along the thickness direction of the metal light-shielding plate substrate and has the opening on the surface; Form the concave portion in the metal light-shielding plate substrate through the dry film resist; and Remove the dry film resist from the metal light-shielding plate substrate formed with the concave portion. [Advantages of the Invention]

[0013] According to the present invention, the light-shielding performance of the metal light-shielding plate can be ensured. Brief Description of the Drawings

[0014] FIG. 1 schematically shows a perspective view of a metal light-shielding plate substrate according to an embodiment of the present invention. FIG. 2 schematically shows a top view of a metal light-shielding plate according to an embodiment of the present invention. FIG. 3 schematically shows a cross-sectional view of a main part of the metal light-shielding plate in FIG. 2. FIG. 4 is a diagram for explaining a method for manufacturing a metal light-shielding plate. FIG. 5 is a diagram for explaining a method of manufacturing a metal light shielding plate. FIG. 6 is a diagram for explaining a method of manufacturing a metal light shielding plate. FIG. 7 is a diagram for explaining a method of manufacturing a metal light shielding plate. FIG. 8 is a diagram for explaining a method of manufacturing a metal light shielding plate. FIG. 9 is a diagram showing an example of a camera module including the metal light shielding plates of FIGS. 2 and 3. FIG. 10 is an image showing an example in which there are no irregularities at the edge of the hole in the metal light shielding plate. FIG. 11 is an image showing an example in which there are irregularities at the edge of the hole in the metal light shielding plate. Embodiment

[0015] Referring to FIGS. 1 to 11, an embodiment of a metal light shielding plate substrate, a metal light shielding plate, a camera module, an electronic device, and a method of manufacturing a metal light shielding plate will be described. Hereinafter, the metal light shielding plate substrate, the metal light shielding plate, the method of manufacturing the metal light shielding plate, the camera module, and the examples will be described.

[0016] [Metal Light Shielding Plate Substrate] The metal light shielding plate substrate 10M shown in FIG. 1 is used for the metal light shielding plate 10 (refer to FIGS. 2 and 3) described later. The metal light shielding plate substrate 10M is a metal layer extending along one surface. The metal light shielding plate substrate 10M is composed of a rolled material having a thickness of 10 μm or more and 50 μm or less. The metal light shielding plate substrate 10M includes a first surface 10MR (surface) and a second surface 10MF. The first surface 10MR and the second surface 10MF are surfaces facing opposite sides in the thickness direction of the metal light shielding plate substrate 10M.

[0017] The first surface 10MR is configured as an example of a surface for disposing a resist. Specifically, it is configured as an example of a surface to which a first dry film resist RR (dry film resist) is attached. The three-dimensional surface roughness Sa of the first surface 10MR is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the first surface 10MR is 2.666 μm or more under a 50-fold field of view. Also, the three-dimensional surface roughness Sa of the first surface 10MR is 0.109 μm or more under a 150-fold field of view, and the three-dimensional surface roughness Sz of the first surface 10MR is 1.289 μm or more under a 150-fold field of view.

[0018] The second surface 10MF is an example of the surface for disposing a resist. Specifically, it is an example of the surface to which the second dry film resist RF (dry film resist) is attached. The three-dimensional surface roughness Sa of the second surface 10MF is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the second surface 10MF is 2.666 μm or more under a 50-fold field of view. Also, the three-dimensional surface roughness Sa of the second surface 10MF is 0.109 μm or more under a 150-fold field of view, and the three-dimensional surface roughness Sz of the second surface 10MF is 1.289 μm or more under a 150-fold field of view.

[0019] The above-mentioned three-dimensional surface roughness Sa and three-dimensional surface roughness Sz are values measured by the method according to ISO 25178. The three-dimensional surface roughness Sa is the arithmetic mean height Sa in a defined area having a predetermined area, and the three-dimensional surface roughness Sz is the maximum height Sz in a defined area having a predetermined area.

[0020] The forming material of the metal light-shielding plate substrate 10M can also be, for example, stainless steel (SUS), that is, an alloy mainly composed of iron and chromium. In addition, the forming material of the metal light-shielding plate substrate 10M can also be other metal materials or alloy materials.

[0021] Based on the above-mentioned metal light-shielding plate substrate 10M, the three-dimensional surface roughness Sa of the first surface 10MR is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the first surface 10MR is 2.666 μm or more under a 50-fold field of view. Therefore, it becomes difficult to form a gap between the first surface 10MR and the first dry film resist RR attached to the first surface 10MR, and the adhesion at the interface between the first surface 10MR of the metal light-shielding plate substrate 10M and the first dry film resist RR can be improved. Also, in the above-mentioned metal light-shielding plate substrate 10M, the three-dimensional surface roughness Sa of the first surface 10MR is 0.109 μm or more under a 150-fold field of view, and the three-dimensional surface roughness Sz of the first surface 10MR is 1.289 μm or more under a 150-fold field of view. Therefore, the adhesion at the interface between the first surface 10MR of the metal light-shielding plate substrate 10M and the first dry film resist RR can be surely improved.

[0022] Furthermore, based on the above-mentioned metal light-shielding plate substrate 10M, the three-dimensional surface roughness Sa of the second surface 10MF is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the second surface 10MF is 2.666 μm or more under a 50-fold field of view. Therefore, in addition to the first surface 10MR, the adhesion between the metal light-shielding plate substrate 10M and the second dry film resist RF can also be improved on the second surface 10MF. Also, in the above-mentioned metal light-shielding plate substrate 10M, the three-dimensional surface roughness Sa of the second surface 10MF is 0.109 μm or more under a 150-fold field of view, and the three-dimensional surface roughness Sz of the second surface 10MF is 1.289 μm or more under a 150-fold field of view. Therefore, the adhesion between the metal light-shielding plate substrate 10M and the second dry film resist RF in the second surface 10MF can be surely improved.

[0023] Also, when the above-mentioned metal light-shielding plate substrate 10M is made of stainless steel, by setting the three-dimensional surface roughnesses Sa and Sz of the first surface 10MR and the second surface 10MF of the metal light-shielding plate substrate 10M as described above, the adhesion between the metal light-shielding plate substrate 10M and the first dry film resist RR and the second dry film resist RF can be effectively improved.

[0024] [Metal Light-Shielding Plate] The metal light-shielding plate 10 shown in FIGS. 2 and 3 is manufactured using the above-mentioned metal light-shielding plate substrate 10M. The metal light-shielding plate 10 includes a first surface 10R (front surface), a second surface 10F, and a hole 10H. The first surface 10R of the metal light-shielding plate 10 corresponds to the first surface 10MR of the metal light-shielding plate substrate 10M. Also, the second surface 10F of the metal light-shielding plate 10 corresponds to the second surface 10MF of the metal light-shielding plate substrate 10M. The hole 10H penetrates between the second surface 10F and the first surface 10R. Similarly to the metal light-shielding plate substrate 10M, the thickness T of the metal light-shielding plate 10 is 10 μm or more and 50 μm or less. In the metal light-shielding plate 10, the second surface 10F is the surface on the light incident side.

[0025] The first surface 10R, the second surface 10F, and the side surface of the hole 10H in the metal light-shielding plate 10 may not be covered with an anti-reflection film (not shown). The anti-reflection film has a lower reflectivity than the metal forming the metal light-shielding plate 10 and has a function of absorbing a part of the light irradiated onto the anti-reflection film. In addition, the anti-reflection film covering the metal light-shielding plate 10 may not completely eliminate the reflection of the light on the metal light-shielding plate 10.

[0026] As shown in FIG. 2, the metal light-shielding plate 10 forms a circular shape in a top view. The hole 10H also forms a circular shape in a top view.

[0027] As shown in FIG. 3, the hole 10H includes a first recess 10H1 and a second recess 10H2. The first recess 10H1 has a first opening H1R on the first surface 10R, and is a recess having a shape that gradually tapers from the first surface 10R toward the second surface 10F. The second recess 10H2 has a second opening H2F on the second surface 10F that is larger than the first opening H1R. The second recess 10H2 has a shape that gradually tapers from the second surface 10F toward the first surface 10R and is connected to the first recess 10H1. The opening of the first recess 10H1 on the side opposite to the first opening H1R is a circular central opening HC.

[0028] In the thickness direction of the metal light shield 10, the depth dimension of the second recess 10H2 is greater than the depth dimension of the first recess 10H1. Also, the central opening HC is located near the first opening H1R. The hole 10H is formed in a conical shape that becomes smaller as it goes from the first surface 10R toward the second surface 10F and as it goes from the second surface 10F toward the first surface 10R.

[0029] In the present embodiment, in a cross-section along a plane orthogonal to the second surface 10F, the side surface (inner surface) of the second recess 10H2 is arc-shaped, and the center of curvature of the side surface of the second recess 10H2 is located outside the metal light shield 10. Also, the side surface (inner surface) of the first recess 10H1 is arc-shaped, and the center of curvature of the side surface of the first recess 10H1 is located outside the metal light shield 10.

[0030] In the metal light shield 10, the diameter of the first opening H1R of the first recess 10H1 is the first diameter DH1, and the diameter of the second opening H2F of the second recess 10H2 is the second diameter DH2. In the present embodiment, since the central opening HC is located near the first opening H1R, the diameter of the central opening HC is approximately equal to the first diameter DH1 of the first recess 10H1.

[0031] The first diameter DH1 is a value set according to the camera module on which the metal light shield 10 is mounted. When the metal light shield 10 is mounted on a camera module of, for example, a smartphone, the first diameter DH1 can also be 0.4 mm or more and 1.0 mm or less. Also, when the metal light shield 10 is mounted on, for example, an in-vehicle camera, the first diameter DH1 can also be 2.0 mm or more and 7.0 mm or less. The percentage (DH1 / DH2 × 100) of the first diameter DH1 with respect to the second diameter DH2 can also be, for example, 80% or more and 99% or less.

[0032] [Method for manufacturing a metal light shield] Next, referring to FIGS. 4 to 8, an example of a method for manufacturing the metal light-shielding plate 10 using the metal light-shielding plate base material 10M will be described. When manufacturing the metal light-shielding plate 10, the metal light-shielding plate base material 10M (FIG. 1) is prepared. When preparing the metal light-shielding plate base material 10M, first, as shown in FIG. 4, a base material 15a made of stainless steel (SUS) and extending along one direction, i.e., the extending direction D1, is prepared. Next, the base material 15a is transported toward the rolling device 50 having a pair of rolling rollers 51 and 52 in such a manner that the extending direction D1 of the base material 15a is parallel to the transporting direction D2 of the transported base material 15a.

[0033] When the base material 15a reaches between the pair of rolling rollers 51 and 52, the base material 15a is rolled by the pair of rolling rollers 51 and 52. Thereby, by reducing the thickness of the base material 15a and stretching the base material 15a in the transporting direction D2, the rolled material 15 as the metal light-shielding plate base material 10M can be obtained. In FIG. 4, the rolled material 15 is wound around the core C, but the rolled material 15 can also be processed in a state of being stretched into a belt shape, for example, without being wound around the core C. The thickness of the rolled material 15 is, for example, 10 μm or more and 50 μm or less.

[0034] Although not shown, in order to remove the residual stress accumulated inside the rolled material 15 formed by rolling the base material 15a, the rolled material 15 can also be annealed. At this time, the rolled material 15 with reduced residual stress can be obtained.

[0035] In the metal light-shielding plate base material 10M composed of the rolled material 15 obtained in the above manner, the three-dimensional surface roughness Sa of the first surface 10MR is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the first surface 10MR is 2.666 μm or more under a 50-fold field of view. Also, the three-dimensional surface roughness Sa of the first surface 10MR is 0.109 μm or more under a 150-fold field of view, and the three-dimensional surface roughness Sz of the first surface 10MR is 1.289 μm or more under a 150-fold field of view. Furthermore, the three-dimensional surface roughness Sa of the second surface 10MF is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the second surface 10MF is 2.666 μm or more under a 50-fold field of view. Also, the three-dimensional surface roughness Sa of the second surface 10MF is 0.109 μm or more under a 150-fold field of view, and the three-dimensional surface roughness Sz of the second surface 10MF is 1.289 μm or more under a 150-fold field of view. The three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz of the above-mentioned metal light-shielding plate base material 10M can be obtained, for example, by transferring the surfaces of the rolling rollers 51 and 52 onto the base material 15a when rolling the base material 15a.

[0036] After preparing the metal light-shielding substrate 10M, as shown in FIG. 5, a first dry film resist RR is disposed on the first surface 10MR of the metal light-shielding substrate 10M. Also, a second dry film resist RF is disposed on the second surface 10MF of the metal light-shielding substrate 10M. The dry film resists RR and RF can be negative resists or positive resists.

[0037] As shown in FIG. 6, by exposing and developing the dry film resists RR and RF, via holes RRh and RFh are formed in the dry film resists RR and RF, and the patterned dry film resists RR and RF can be obtained. More specifically, by exposing and developing the first dry film resist RR, a first via hole RRh is formed in the first dry film resist RR. The first via hole RRh is a hole in the first dry film resist RR for forming a first recess 10H1 having a first opening H1R on the first surface 10MR (see FIGS. 2 and 7). Also, by exposing and developing the second dry film resist RF, a second via hole RFh is formed in the second dry film resist RF. The second via hole RFh is a hole in the second dry film resist RF for forming a second recess 10H2 having a second opening H2F on the second surface 10MF (see FIGS. 2 and 8).

[0038] As shown in FIG. 7, via the first dry film resist RR disposed on the first surface 10MR, a first recess 10H1 that is recessed along the thickness direction of the metal light-shielding substrate 10M and has a first opening H1R on the first surface 10MR is formed in the metal light-shielding substrate 10M. The first recess 10H1 has a shape that gradually tapers from the first surface 10MR toward the second surface 10MF. The first recess 10H1 is the first recess 10H1 of the metal light-shielding plate 10.

[0039] When forming the first recess 10H1, an etching solution capable of etching the metal light-shielding substrate 10M is used to etch the metal light-shielding substrate 10M. In addition, before etching the metal light-shielding substrate 10M, the second dry film resist RF is covered with a second surface protective film PMF that is resistant to the etching solution. The second surface protective film PMF can also bury the second via hole RFh of the second dry film resist RF or can only cover the second via hole RFh. By covering the second dry film resist RF with the second surface protective film PMF, etching of the second surface 10MF and the first surface 10MR of the metal light-shielding substrate 10M simultaneously can be suppressed.

[0040] In addition, in the case where the first concave portion 10H1 is formed by etching the first surface 10MR, the first concave portion 10H1 having a depth greater than the distance from the first surface 10R in the metal light-shielding plate 10 to the central opening HC (refer to FIG. 3) is formed.

[0041] As shown in FIG. 8, after the first concave portion 10H1 is formed, the second dry film resist RF disposed on the second surface 10MF is interposed, and the second concave portion 10H2 that is recessed along the thickness direction of the metal light-shielding plate substrate 10M and has a second opening H2F on the second surface 10MF is formed in the metal light-shielding plate substrate 10M. The second concave portion 10H2 has a shape that gradually tapers from the second surface 10MF toward the first surface 10MR. Thereby, the second concave portion 10H2 is connected to the first concave portion 10H1 to form the central opening HC. The second concave portion 10H2 is the second concave portion 10H2 of the metal light-shielding plate 10. Also, the central opening HC is the central opening HC of the metal light-shielding plate 10.

[0042] When the second concave portion 10H2 is formed, similarly to when the first concave portion 10H1 is formed, an etching solution capable of etching the metal light-shielding plate substrate 10M is used to etch the metal light-shielding plate substrate 10M. In addition, before etching the metal light-shielding plate substrate 10M, the first dry film resist RR is removed from the first surface 10MR of the metal light-shielding plate substrate 10M. Then, before etching the metal light-shielding plate substrate 10M, the first surface 10MR of the metal light-shielding plate substrate 10M is covered with the first surface protective film PMR that is resistant to the etching solution, and the first concave portion 10H1 is filled. By covering the first surface 10MR of the metal light-shielding plate substrate 10M with the first surface protective film PMR, simultaneous etching of the first surface 10MR side of the metal light-shielding plate substrate 10M and the second surface 10MF of the metal light-shielding plate substrate 10M can be suppressed.

[0043] Regarding the etching of the second recess 10H2, with the first recess 10H1 covered by the first surface protective film PMR, the second surface 10MF of the metal light-shielding plate substrate 10M is etched. Therefore, after the etching of the second surface 10MF reaches the first surface protective film PMR, the supply of the etching solution to the metal light-shielding plate substrate 10M is controlled by the first surface protective film PMR. Thereby, even when the thickness of the metal light-shielding plate substrate 10M is in a wide range of 10 μm or more and 50 μm or less, the accuracy of the cross-sectional shape of the second recess 10H2 can be improved. In contrast, when the first recess 10H1 is not filled with the first surface protective film PMR, when the first recess 10H1 and the second recess 10H2 are connected to penetrate the metal light-shielding plate substrate 10M, the etching solution will leak to the first surface 10MR of the metal light-shielding plate substrate 10M through the connection portion between the first recess 10H1 and the second recess 10H2. As a result, the accuracy of the shape of the first recess 10H1 and the shape of the second recess 10H2 are reduced.

[0044] After the first recess 10H1 and the second recess 10H2 are formed in the metal light-shielding plate substrate 10M, the second dry film resist RF is removed from the second surface 10MF, and the first surface protective film PMR is removed from the first surface 10MR. In this way, the metal light-shielding plate 10 shown in FIGS. 2 and 3 can be obtained.

[0045] In the above method for manufacturing the metal light-shielding plate 10, for example, an antireflection film covering the second surface 10MF, the first surface 10MR, and the side surfaces of the first recess 10H1 and the second recess 10H2 may also be formed after the second dry film resist RF and the first surface protective film PMR are removed from the metal light-shielding plate substrate 10M. As described above, the antireflection film has a lower reflectance than the metal light-shielding plate substrate 10M and has the function of absorbing a part of the light incident on the antireflection film. The antireflection film, for example, has a black film. The antireflection film can also be formed on the metal light-shielding plate substrate 10M using a film-forming method such as sputtering or evaporation. Or, the antireflection film can also be formed on the metal light-shielding plate substrate 10M by bringing a liquid for forming the antireflection film into contact with the metal light-shielding plate substrate 10M.

[0046] In addition, in the above method for manufacturing the metal light-shielding plate 10, the first dry film resist RR may not be removed before forming the first surface protective film PMR. At this time, as long as the first dry film resist RR is covered and the first surface protective film PMR filled in the first recess 10H1 is formed. Also, the first surface protective film PMR can be removed from the first surface 10MR together with the first dry film resist RR after the second recess 10H2 is formed by etching the second surface 10MF.

[0047] [Camera Module] Next, the camera module will be described with reference to FIG. 9. In addition, FIG. 9 schematically shows the configuration of the camera module.

[0048] As shown in FIG. 9, the camera module 20 includes the above-described metal light shield 10, a lens 21, and an imaging element 22. The lens 21 transmits the light passing through the hole of the metal light shield 10. The light transmitted through the lens 21 enters the imaging element 22. The metal light shield 10 is located on the light incident side with respect to the lens 21 in a state where the first surface 10R faces the lens 21. Compared with the case where the second surface 10F of the metal light shield 10 faces the lens 21, by passing through the central opening HC and then being reflected by the side surface of the hole 10H, the light incident on the lens 21 can be restricted.

[0049] The diameter of the central opening HC of the metal light shield 10 may also be sized to be equal to or less than the effective diameter of the lens 21. Thereby, the light passing through the central opening HC can be suppressed from entering the outside of the effective diameter of the lens 21. Therefore, unintended light can be suppressed from entering the imaging element 22.

[0050] The imaging element 22 may also be a CCD image sensor or a CMOS image sensor. In the camera module 20, one metal light shield 10 and one lens 21 adjacent to the metal light shield 10 on the optical axis of the light passing through the metal light shield 10 form one lens unit. The camera module 20 may also include a plurality of lens units. In addition, the camera module is not limited to, for example, including the above-described lens 21, imaging element 22, etc., and at least one metal light shield 10 is sufficient.

[0051] The camera module 20 is mounted on various electronic devices. The electronic device includes the above-described camera module 20 and a housing that supports the camera module 20. The electronic device may also be, for example, a smart phone, a tablet personal computer, a notebook personal computer, etc.

[0052] In the metal light-shielding plate substrate 10M of this embodiment, the three-dimensional surface roughness Sa of the first surface 10MR (surface) is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the first surface 10MR is 2.666 μm or more under a 50-fold field of view. Therefore, the adhesion at the interface between the first surface 10MR of the metal light-shielding plate substrate 10M and the first dry film resist RR can be improved. Thereby, when forming the first recess 10H1 in the metal light-shielding plate substrate 10M using the first dry film resist RR, unevenness can be suppressed at the edge of the first opening H1R of the first recess 10H1 and on the side surface (inner surface) of the first recess 10H1. Therefore, in the manufactured metal light-shielding plate 10, unevenness can be suppressed at the edge of the hole 10H, and deviation in the size of the hole 10H can be suppressed. As a result, the light-shielding performance of the metal light-shielding plate 10 can be ensured.

[0053] Also, in the metal light-shielding plate substrate 10M of this embodiment, the three-dimensional surface roughness Sa of the first surface 10MR is 0.109 μm or more under a 150-fold field of view, and the three-dimensional surface roughness Sz of the first surface 10MR is 1.289 μm or more under a 150-fold field of view. Therefore, the adhesion at the interface between the first surface 10MR of the metal light-shielding plate substrate 10M and the first dry film resist RR can be surely improved. Thereby, when forming the first recess 10H1 in the metal light-shielding plate substrate 10M, unevenness can be more surely suppressed at the edge of the first opening H1R of the first recess 10H1 and on the side surface (inner surface) of the first recess 10H1.

[0054] Also, in the metal light-shielding plate substrate 10M of this embodiment, the three-dimensional surface roughness Sa of the surface 10MF on the side opposite to the first surface 10MR, that is, the second surface, is 0.142 μm or more under a 50-fold field of view, and the three-dimensional surface roughness Sz of the second surface 10MF is 2.666 μm or more under a 50-fold field of view. Therefore, in addition to the first surface 10MR, the adhesion between the metal light-shielding plate substrate 10M and the second dry film resist RF can also be improved on the second surface 10MF. Thereby, when forming the second recess 10H2 in the metal light-shielding plate substrate 10M using the second dry film resist RF, unevenness can be suppressed at the edge of the second opening H2F of the second recess 10H2 and on the side surface (inner surface) of the second recess 10H2. Therefore, in the manufactured metal light-shielding plate 10, unevenness can be more effectively suppressed at the edge of the hole 10H, and deviation in the size of the hole 10H can be suppressed. As a result, the light-shielding performance of the metal light-shielding plate 10 can be ensured.

[0055] Further, in the metal light-shielding plate base material 10M of the present embodiment, the three-dimensional surface roughness Sa of the second surface 10MF is 0.109 μm or more under a 150-fold field of view, and the three-dimensional surface roughness Sz of the second surface 10MF is 1.289 μm or more under a 150-fold field of view. Therefore, the adhesion between the metal light-shielding plate base material 10M and the second dry film resist RF on the second surface 10MF can be surely improved. Thereby, when forming the second concave portion 10H2 in the metal light-shielding plate base material 10M, unevenness can be more surely suppressed at the edge of the second opening H2F of the second concave portion 10H2 and on the side surface (inner surface) of the second concave portion 10H2.

[0056] Further, the metal light-shielding plate base material 10M of the present embodiment is made of an alloy mainly composed of iron and chromium. Therefore, the adhesion between the metal light-shielding plate base material 10M and the first dry film resist RR and the second dry film resist RF can be effectively improved. As a result, unevenness can be effectively suppressed at the edges of the first and second openings H1R and H2F formed in the first and second concave portions 10H1 and 10H2 of the metal light-shielding plate 10 and on the side surfaces (inner surfaces) of the first and second concave portions 10H1 and 10H2.

[0057] The metal light-shielding plate base material of the present invention will be further described using experimental examples (Examples 1 to 6 and Comparative Examples 1 to 3). The technical scope of the present invention is not limited by any specific content of the experimental examples.

[0058] [Measurement of surface roughness] The metal light-shielding plate base materials of Examples 1 to 6 and Comparative Examples 1 to 3 were all made of stainless steel foils having a thickness of 25 μm. Regarding these metal light-shielding plate base materials of Examples 1 to 6 and Comparative Examples 1 to 3, the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz of the first surface and the second surface were measured by the following method.

[0059] Using a shape analysis laser microscope (VK-X210, manufactured by KEYENCE CORPORATION) equipped with 50-fold and 150-fold objective lenses, the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz were measured. In the case of the 50-fold lens, as the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz, the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz of a surface having a width of about 280 μm in one direction and a width of about 220 μm in a direction orthogonal to the one direction were measured. In the case of the 150-fold lens, as the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz, the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz of a surface having a width of about 90 μm in one direction and a width of about 70 μm in a direction orthogonal to the one direction were measured. In addition, the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz are measured in accordance with the directions of ISO 25178.

[0060] For each of the metal light-shielding substrate of Examples 1 to 6 and Comparative Examples 1 to 3, the results of measuring the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz at a 50-fold lens and the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz at a 150-fold lens are shown in Table 1. Table 1 shows only the measurement results of the three-dimensional surface roughness Sa and the three-dimensional surface roughness Sz of the first surface, but the measurement results of the second surface are the same as those of the first surface.

[0061] [Table 1] ×50 ×150 Sa [μm] Sz [μm] Sa [μm] Sz [μm] Example 1 0.151 2.910 0.116 1.338 Example 2 0.165 2.982 0.111 1.494 Example 3 0.159 2.896 0.110 1.429 Example 4 0.153 2.823 0.109 1.304 Example 5 0.145 2.750 0.113 1.320 Example 6 0.142 2.666 0.111 1.289 Comparative Example 1 0.099 1.808 0.078 0.886 Comparative Example 2 0.096 1.691 0.071 0.803 Comparative Example 3 0.093 1.631 0.061 0.727

[0062] As shown in Table 1, in the metal light-shielding substrate of Example 1, the three-dimensional surface roughness Sa is 0.151 μm at a 50-fold field of view (×50), and the three-dimensional surface roughness Sz is 2.910 μm at a 50-fold field of view. Also, in the metal light-shielding substrate of Example 1, the three-dimensional surface roughness Sa is 0.116 μm at a 150-fold field of view (×150), and the three-dimensional surface roughness Sz is 1.338 μm at a 150-fold field of view.

[0063] In the metal light-shielding substrate of Example 2, the three-dimensional surface roughness Sa is 0.165 μm at a 50-fold field of view, and the three-dimensional surface roughness Sz is 2.982 μm at a 50-fold field of view. Also, in the metal light-shielding substrate of Example 2, the three-dimensional surface roughness Sa is 0.111 μm at a 150-fold field of view, and the three-dimensional surface roughness Sz is 1.494 μm at a 150-fold field of view.

[0064] In the metal light-shielding substrate of Example 3, the three-dimensional surface roughness Sa is 0.159 μm at a 50-fold field of view, and the three-dimensional surface roughness Sz is 2.896 μm at a 50-fold field of view. Also, in the metal light-shielding substrate of Example 3, the three-dimensional surface roughness Sa is 0.110 μm at a 150-fold field of view, and the three-dimensional surface roughness Sz is 1.429 μm at a 150-fold field of view.

[0065] In the metal light-shielding substrate of Example 4, the three-dimensional surface roughness Sa is 0.153 μm at a 50-fold field of view, and the three-dimensional surface roughness Sz is 2.823 μm at a 50-fold field of view. Also, in the metal light-shielding substrate of Example 4, the three-dimensional surface roughness Sa is 0.109 μm at a 150-fold field of view, and the three-dimensional surface roughness Sz is 1.304 μm at a 150-fold field of view.

[0066] In the metal light-shielding substrate of Example 5, the three-dimensional surface roughness Sa is 0.145 μm at a 50-fold field of view, and the three-dimensional surface roughness Sz is 2.750 μm at a 50-fold field of view. Also, in the metal light-shielding substrate of Example 5, the three-dimensional surface roughness Sa is 0.113 μm at a 150-fold field of view, and the three-dimensional surface roughness Sz is 1.320 μm at a 150-fold field of view.

[0067] In the metal light-shielding substrate of Example 6, the three-dimensional surface roughness Sa is 0.142 μm at a 50-fold field of view, and the three-dimensional surface roughness Sz is 2.666 μm at a 50-fold field of view. Also, in the metal light-shielding substrate of Example 6, the three-dimensional surface roughness Sa is 0.111 μm at a 150-fold field of view, and the three-dimensional surface roughness Sz is 1.289 μm at a 150-fold field of view.

[0068] In the metal light-shielding substrate of Comparative Example 1, the three-dimensional surface roughness Sa is 0.099 μm at a 50-fold field of view, and the three-dimensional surface roughness Sz is 1.808 μm at a 50-fold field of view. Also, in the metal light-shielding substrate of Comparative Example 1, the three-dimensional surface roughness Sa is 0.078 μm at a 150-fold field of view, and the three-dimensional surface roughness Sz is 0.886 μm at a 150-fold field of view.

[0069] In the metal light-shielding substrate of Comparative Example 2, the three-dimensional surface roughness Sa is 0.096 μm at a 50-fold field of view, and the three-dimensional surface roughness Sz is 1.691 μm at a 50-fold field of view. Also, in the metal light-shielding substrate of Comparative Example 2, the three-dimensional surface roughness Sa is 0.071 μm at a 150-fold field of view, and the three-dimensional surface roughness Sz is 0.803 μm at a 150-fold field of view.

[0070] In the metal light-shielding substrate of Comparative Example 3, the three-dimensional surface roughness Sa is 0.093 μm at a 50-fold field of view, and the three-dimensional surface roughness Sz is 1.631 μm at a 50-fold field of view. Also, in the metal light-shielding substrate of Comparative Example 3, the three-dimensional surface roughness Sa is 0.061 μm at a 150-fold field of view, and the three-dimensional surface roughness Sz is 0.727 μm at a 150-fold field of view.

[0071] Using the metal light-shielding substrate of Examples 1 to 6 and Comparative Examples 1 to 3 described above, metal light-shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3 were manufactured in the same procedure as the manufacturing method shown in FIGS. 5 to 8. That is, after forming the first recess by etching the metal light-shielding substrate from the first surface of the metal light-shielding substrate, the second recess was formed by etching the metal light-shielding substrate from the second surface of the metal light-shielding substrate. Thereby, a metal light-shielding plate having holes formed by the first recess and the second recess was obtained. The target value of the first diameter of the first recess was set to 491 μm, and the target value of the second diameter of the second recess was set to 571 μm. A plurality of holes were formed in each of the metal light-shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3.

[0072] Regarding each of the metal light-shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3 manufactured as described above, the edge of the hole 10H was identified in the laser microscope field of view illustrated in FIGS. 10 and 11, and the unevenness of the edge of the hole 10H was evaluated. The edge of the hole 10H illustrated in FIG. 10 without unevenness was designated as "○" (good), and the edge of the hole 10H having unevenness as illustrated in FIG. 11 was designated as "×" (poor). The evaluation results of the unevenness of the edge of the hole 10H are shown in Table 2.

[0073] [Table 2] Evaluation of unevenness Example 1 ○ Example 2 ○ Example 3 ○ Example 4 ○ Example 5 ○ Example 6 ○ Comparative Example 1 × Comparative Example 2 × Comparative Example 3 ×

[0074] As shown in Table 2, in the metal light-shielding plates of Comparative Examples 1 to 3, there are irregularities at the edge of the hole 10H. This is considered to be due to the fact that in the metal light-shielding plate base materials used for manufacturing the metal light-shielding plates of Comparative Examples 1 to 3, the three-dimensional surface roughness Sa is less than 0.142 μm at a 50-fold field of view, and the three-dimensional surface roughness Sz is less than 2.666 μm at a 50-fold field of view. Also, it is considered to be due to the fact that in the metal light-shielding plates of Comparative Examples 1 to 3, the three-dimensional surface roughness Sa is less than 0.109 μm at a 150-fold field of view, and the three-dimensional surface roughness Sz is less than 1.289 μm at a 150-fold field of view. On the other hand, in the metal light-shielding plates of Examples 1 to 6, there are no irregularities at the edge of the hole 10H. This is considered to be due to the fact that in the metal light-shielding plates of Examples 1 to 6, the three-dimensional surface roughness Sa is 0.142 μm or more at a 50-fold field of view, and the three-dimensional surface roughness Sz is 2.666 μm or more at a 50-fold field of view. Also, it is considered to be due to the fact that in the metal light-shielding plates of Examples 1 to 6, the three-dimensional surface roughness Sa is 0.109 μm or more at a 150-fold field of view, and the three-dimensional surface roughness Sz is 1.289 μm or more at a 150-fold field of view.

[0075] Also, the first diameter DH1 (refer to FIG. 3) in the first recess of a plurality of holes formed in each of the metal light-shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3 manufactured was measured. The number (n [pieces]) of holes for which the first diameter was measured was 3200 in each of the metal light-shielding plates of Examples 1 to 6, and 648 in Comparative Examples 1 to 3. For each of the metal light-shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3, the average value (ave [μm]) of the first diameter, the maximum value (max [μm]) of the first diameter, the minimum value (min [μm]) of the first diameter, the difference between the maximum value and the minimum value of the first diameter (max - min [μm]), and the standard deviation (σ [μm]) were obtained. The results are shown in Table 3.

[0076] [Table 3] First diameter Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Average value [μm] 492 492 489 489 489 491 491 490 490 Maximum value [μm] 494 494 491 490 494 495 499 498 497 Minimum value [μm] 490 490 487 487 487 488 487 487 487 Difference between maximum and minimum values [μm] 4 4 4 3 7 7 12 11 10 σ [μm] 1.0 0.9 0.9 0.8 1.4 1.3 2.6 2.4 2.2 n [pcs] 3,200 3,200 3,200 3,200 3,200 3,200 648 648 648

[0077] As shown in Table 3, in the metal light-shielding plates of Comparative Examples 1 to 3, the difference in the first diameter (max - min [μm]) was 10 μm or more, which was relatively large. This is considered to be due to the fact that in the metal light-shielding plates of Comparative Examples 1 to 3, there were irregularities at the edge of the hole. On the other hand, in the metal light-shielding plates of Examples 1 to 6, the difference in the first diameter (max - min [μm]) was 7 μm or less, which was relatively small. This is considered to be due to the fact that in the metal light-shielding plates of Examples 1 to 6, there were no irregularities at the edge of the hole.

[0078] Also, based on the standard deviation σ of the first diameter in each of the metal light-shielding plates of Examples 1 to 6 and Comparative Examples 1 to 3 (refer to Table 3), the dimensional deviation of the first diameter was evaluated. Those with a standard deviation σ of 1.0 μm or less were rated as "◎" (excellent; very small dimensional deviation), those with a standard deviation σ of 2.0 μm or less were rated as "○" (good; small dimensional deviation), and those exceeding 2.0 μm were rated as "×" (poor; large dimensional deviation). The evaluation results of the dimensional deviation of the first diameter are shown in Table 4.

[0079] [Table 4] Evaluation of Dimensional Deviation Example 1 ◎ Example 2 ◎ Example 3 ◎ Example 4 ◎ Example 5 ○ Example 6 ○ Comparative Example 1 × Comparative Example 2 × Comparative Example 3 ×

[0080] As shown in Table 4, in the metal light-shielding plates of Comparative Examples 1 to 3, the evaluation of the dimensional deviation of the first diameter of the hole was all "×". This is considered to be due to the fact that in the metal light-shielding plates of Comparative Examples 1 to 3, there were irregularities at the edge of the hole. On the other hand, in the metal light-shielding plates of Examples 1 to 4, the evaluation of the dimensional deviation of the first diameter of the holes was all "◎". Also, in the metal light-shielding plates of Examples 5 to 6, the evaluation of the dimensional deviation of the first diameter of the holes was all "○". This is considered to be due to the fact that in the metal light-shielding plates of Examples 1 to 6, there are no irregularities at the edges of the holes. [Industrial Applicability]

[0081] According to the present invention, the light-shielding performance of the metal light-shielding plate can be ensured.

[0082] 10: Metal light-shielding plate 10F: Second surface 10R: First surface (front surface) 10H: Hole 10H1: First recess (recess) 10M: Metal light-shielding plate substrate 10MF: Second surface 10MR: First surface (front surface) 20: Camera module 21: Lens 22: Imaging element H1R: First opening (opening) RF: Second dry film resist RR: First dry film resist RRh: First through hole (through hole)

Claims

1. A metal light-shielding plate substrate, which is a metal light-shielding plate substrate used in metal light-shielding plates, wherein the three-dimensional surface roughness Sa of the surface of the aforementioned metal light-shielding plate substrate is 0.142 μm or more under 50x magnification, and the three-dimensional surface roughness Sz of the aforementioned surface is 2.666 μm or more under 50x magnification.

2. The metal light-shielding substrate of claim 1, wherein the three-dimensional surface roughness Sa of the aforementioned surface is 0.109 μm or more under 150x magnification, and the three-dimensional surface roughness Sz of the aforementioned surface is 1.289 μm or more under 150x magnification.

3. The metal light-shielding substrate of claim 1 or 2, wherein the aforementioned surface is a first surface, the surface opposite to the aforementioned first surface is a second surface, and the three-dimensional surface roughness Sa of the aforementioned second surface is 0.142 μm or more under 50x magnification, and the three-dimensional surface roughness Sz of the aforementioned second surface is 2.666 μm or more under 50x magnification.

4. The metal light-shielding substrate of claim 3, wherein the three-dimensional surface roughness Sa of the aforementioned second surface is 0.109 μm or more under 150x magnification, and the three-dimensional surface roughness Sz of the aforementioned second surface is 1.289 μm or more under 150x magnification.

5. The metal light-shielding substrate of claim 1 or 2, wherein the aforementioned metal light-shielding substrate is made of an alloy with iron and chromium as the main components.

6. A metal light-shielding plate, which uses the metal light-shielding plate substrate as claimed in claim 1 or 2.

7. A camera module that uses the metal light shield as claimed in claim 6.

8. An electronic device that uses the camera module of claim 7.

9. A method for manufacturing a metal light-shielding plate, comprising: preparing a metal light-shielding plate substrate, the metal light-shielding plate substrate having a surface configured for attaching a dry film resist, and forming an opening by etching using a patterned dry film resist, wherein the three-dimensional surface roughness Sa of the surface is 0.142 μm or more at 50x magnification, and the three-dimensional surface roughness Sz of the surface is 2.666 μm or more at 50x magnification; disposing the dry film resist on the surface; forming a through-hole in the dry film resist, the through-hole being used to form a recess in the metal light-shielding plate substrate, the recess being recessed along the thickness direction of the metal light-shielding plate substrate, and having the opening on the surface; separating the dry film resist and forming the recess in the metal light-shielding plate substrate; and removing the dry film resist from the metal light-shielding plate substrate in which the recess is formed.

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