JPH1053858A - Porous metallic sheet and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a classifying plate capable of exactly classifying particulates coated with metals on their surfaces without contaminating the surfaces of the particulates. SOLUTION: A photoresist 11 is laminated and formed on the surface of a substrate 10 and a photomask 12 opened with many holes is superposed on the surface of the photoresist 11. The photoresist is then subjected to exposure and development processing, by which the projections 11a of the cured photoresist 11 are formed on the surface of the substrate 11 and thereafter, a metallic plate 2 below the height of the projections 11a is laminated and formed by means, such as plating or sputtering, on the substrate 10. The projections 11a of the substrate 10 and the photoresist 11 are then dissolved away.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous metal plate used for classifying spherical fine particles used as various synthetic resin molding materials, metal materials for soldering, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art True spherical fine particles (flow beads) are usually formed from polyethylene or ethylene-acrylic acid copolymer resin as raw materials, and have excellent fluidity and dispersibility. It is used as a matting agent for paints, adhesives, ink modifiers, rubber release agents or cosmetic materials. In particular, if the surface is coated with a metal such as Cu or Ni, or their alloys, or other alloys by means of ion sputtering, vapor deposition, plating, etc., and then surface-treated, it can be handled as a metal powder having a low specific gravity. It is widely used as an additive for a conductive material or an electronic material.

[0003] By the way, such fine particles are produced in various particle sizes from several tens to several hundreds of microns depending on the application. For example, when they are used for a resin molding material or a metal material for soldering. In order to stabilize molding conditions and soldering conditions, it is necessary to make the particle size uniform, and sieving using a classifying plate or the like is indispensable. However, since the conventional classification plate is formed by a wire mesh, it is difficult to make the area of the sieve, that is, the opening, uniform, and accurate classification cannot be performed.

Further, since the sieve is formed by a combination of wires constituting a wire mesh, the shape is quadrangular, and corners with steps are formed at the four corners. Therefore, there is a problem that bridges are easily formed, clogging occurs, and quick and accurate classification is difficult. Further, since the material of the metal wire forming the wire net is iron-based, Cu-based, or the like, for example, in the case of fine particles having a surface coated with Pt or the like, the worn iron-based or Cu-based metal components are fine particles. Adhere to the surface,
There was also a problem that the fine particles were contaminated.

The present invention has been made in view of the above circumstances, and has as its object to uniformize the opening of the sieve, to improve the classification accuracy remarkably, hardly cause clogging, and to achieve smoothness. It is an object of the present invention to provide a perforated metal plate and a method for producing the same, which can perform an appropriate classification.

[0006]

According to a first aspect of the present invention, there is provided a porous metal plate having a metal layer having a thickness equal to or less than the height of the projections on a surface of the substrate on which a large number of projections are formed. The projection is removed.

According to a second aspect of the present invention, there is provided a method for manufacturing a perforated metal plate, comprising forming a required thickness layer of a photoresist on a substrate surface,
A photomask having a pattern of a desired shape prepared in advance is superposed on the surface, exposed and developed, and a number of protrusions of photoresist having a diameter corresponding to a predetermined hole diameter are formed on the surface of the substrate, and vapor-deposited on the surface of the substrate. Forming a metal layer having a thickness equal to or less than the height of the projection by plating or sputtering, and then dissolving and removing the substrate and the projection.

In the first and second aspects of the present invention, the use of the photolithography technique makes it easy to make the area (width) of the holes uniform and small, and to form the holes into a flat surface. Accurate classification is possible with less occurrence of bridges.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a partially enlarged view of a classifier according to the present invention, in which 1 is a classifier, 2 is a metal plate constituting the classifier 1, and 3 is a sieve formed on the metal plate 2. The metal plate 2 is made of the same kind of metal as the metal coated on the surface of the fine particles, for example, Ni, Cu, A
1 or an alloy thereof or an alloy of these and other metals, and is formed to have a uniform thickness mainly as a plating layer or a sputtered layer, on which a large number of sieves 3 are formed. The sieve 3 has a uniform diameter substantially the same as or slightly larger than the diameter of the fine particles to be classified.

The metal plate 2 is made of the same kind of metal as the metal coated on the surface of the fine particles on the surface of the underlying material (metal or synthetic resin), ie, Ni, Cu, Al or an alloy thereof, or an alloy other than these. , Or Pt, Au, P
A white metal element such as d or Rh may be used alone or an alloy thereof may be plated. The sieve 3 is a case where the sieve 3 is usually formed with a uniform density over the entire surface of the metal plate 2,
The present invention is not limited to this. For example, a predetermined number may be collectively formed into a plurality of islands. Also, the shape of the sieve 3 is shown as a perfect circle, but as long as the maximum diameter portion satisfies a condition substantially the same as or slightly larger than that of the fine particles, a square as shown in FIG. It may be formed into a polygon such as a hexagon as shown in (b), or an ellipse, square or rectangle.

Next, a method of manufacturing such a classifying plate 1 utilizing the photolithography technique will be described. FIG. 3 is a process explanatory view showing a main manufacturing process of the classifying plate 1 in a cross section. First, a flat substrate 10 made of metal such as Al, Cu, or an alloy as shown in FIG. 3A, glass, or synthetic resin is prepared, and its surface is exposed as shown in FIG. 3B. A negative type or opposite positive type photoresist 11 is formed by lamination.

A band-like metal foil or a synthetic resin band-like sheet is used as the substrate 10, and the photoresist 11 is coded using a roll coater or the like. The thickness of the coating film of the photoresist 11 is set to a thickness corresponding to the thickness of the metal plate 2 shown in FIG. As a material of the photoresist 11, for example, either a negative type such as photosensitive polyimide or a positive type may be used.

Further, as shown in FIG. 3C, a photomask 12 having a large number of holes 12a formed by photolithography is superimposed on the surface of the photoresist (for example, a negative photoresist). 12 is irradiated with ultraviolet rays from the front side, and is exposed and developed. FIG. 4 is a partially enlarged perspective view of the surface of the substrate 10 after development,
Since the UV-irradiated portion is hardened, the non-irradiated portion of the UV-ray is removed by performing the developing process, and a large number of protrusions 11a of the cured photoresist 11 are formed on the surface of the substrate 10.

Next, as shown in FIG. 3 (e), the surface of the substrate 10 is coated with Ni, Cu, Al or an alloy thereof, or another alloy thereof by plating, sputtering or vapor deposition. After laminating to a thickness corresponding to the height to form a metal layer (a portion to be the metal plate 2), the substrate 10 and the protrusions 11
a by dissolving or removing the metal layer and the substrate 10 and the protrusions 11
a is peeled off. As a result, as shown in FIG. 3F, the sieve 3
Is formed, and a classifying plate 1 as shown in FIG. 1 is obtained. Although the embodiment has described the classifying plate 1 and the method of manufacturing the classifying plate, the present invention is not limited to this, and Au, Pt,
By using a white metal such as Pd or Rh, it can be used, for example, as a catalyst material for a gas reaction or as a corrosion-resistant filter for a corrosive gas or liquid.

The means for forming protrusions on the surface of the substrate 10 is not particularly limited to the above-described method. For example, as the substrate 10, Al is sputtered on the surface of a base material such as a synthetic resin strip film. A photoresist is formed on the entire surface of the substrate 10 except for a portion corresponding to the sieve 3 on the surface thereof, and a predetermined pretreatment is applied to a portion corresponding to the opening 3 to perform electroless processing. After nickel plating, the photoresist may be removed to form Ni projections on the surface of the Al film.

Further, in the embodiment of the present invention, a case is shown in which the protrusion has a single-layer structure of only a photoresist, but when the thickness of the metal plate 2 in the classifying plate 1 is increased, the height of the protrusion itself must be increased. There is. In this case, using a photosensitive polyimide as a photoresist, applying a photomask in the above-described process, exposing and developing, first, a polyimide protrusion is formed, and then a metal film is formed on the entire surface by sputtering, Next, by lifting off the metal film in the other part except the surface of the protrusion and the vicinity thereof, the protrusion becomes higher by the thickness of the metal film in addition to the height of the original polyimide, and a protrusion having a high aspect ratio is formed. The metal layer can be formed, and the thickness of the metal layer can be increased accordingly. In addition, such a classifying plate is used by being mounted on an appropriate reinforcing frame.

[0017]

As described above, in the first and second inventions, since the sieve is formed by the photolithography technique, the sieve can be formed on a flat metal plate. The hole diameter of the sieve is high in accuracy, the clogging hardly occurs, and uniform and smooth classification can be performed.

[Brief description of the drawings]

FIG. 1 is a partially enlarged view of a classification plate according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view showing another example of a classifying plate.

FIG. 3 is a process explanatory view showing main manufacturing steps of a classifying plate according to an embodiment of the present invention.

FIG. 4 is a partially enlarged perspective view showing a substrate surface after development in a step shown in FIG. 3;

[Explanation of symbols]

 Reference Signs List 1 Classification plate 2 Metal plate 3 Sieve 10 Substrate 11 Photoresist 12 Photomask

Claims (2)

[Claims] 1. A porous metal plate comprising: a metal layer having a thickness equal to or less than the height of the projections formed on a surface of a substrate on which a number of projections are formed; and removing the substrate and the projections. 2. A required thickness layer of a photoresist is formed on the surface of a substrate, and a photomask having a pattern of a desired shape prepared in advance is exposed and developed on the surface, and the surface of the substrate is exposed to a predetermined hole diameter. After forming a large number of protrusions of photoresist having a diameter, depositing, plating or sputtering on the surface of the substrate to form a metal layer having a thickness equal to or less than the height of the protrusions, then dissolving and removing the substrate and the protrusions A method for producing a perforated metal plate.