阅读说明：本技术 电镀金属导线的制作方法 (Method for manufacturing electroplated metal wire ) 是由 许铭案 谢东宏 陈香婷 于 2019-09-27 设计创作，主要内容包括：本发明公开了一种电镀金属导线的制作方法,包含：在一透明基板上形成一种子金属导线层,该种子金属导线层的导线已制作完成；在该种子金属导线层的上方形成一光阻层；在该透明基板的另一面提供一散射层；以该种子金属导线层作为一光罩层,经由该散射层对该光阻层进行散射型曝光；移除未被曝光的该光阻层,使该种子金属导线层暴露出来；电镀该种子金属导线层至预定的一厚度而构成一金属导线层；及移除剩余的该光阻层。本发明方法制程简单、容易施作、且成本低,大幅提高了高深宽比电镀制程的良率。(The invention discloses a method for manufacturing an electroplated metal wire, which comprises the following steps: forming a seed metal wire layer on a transparent substrate, wherein the wire of the seed metal wire layer is manufactured; forming a photoresist layer on the seed metal wire layer; providing a scattering layer on the other side of the transparent substrate; using the seed metal wire layer as a mask layer to perform scattering type exposure on the photoresist layer through the scattering layer; removing the unexposed photoresist layer to expose the seed metal wire layer; electroplating the seed metal wire layer to a predetermined thickness to form a metal wire layer; and removing the residual photoresist layer. The method of the invention has simple process, easy operation and low cost, and greatly improves the yield of the electroplating process with high depth-to-width ratio.)

1. A method for manufacturing a plated metal wire, comprising:

forming a seed metal wire layer on a transparent substrate, wherein the wire of the seed metal wire layer is manufactured;

forming a photoresist layer on the seed metal wire layer;

providing a scattering layer on the other side of the transparent substrate;

using the seed metal wire layer as a mask layer to perform scattering type exposure on the photoresist layer through the scattering layer;

removing the unexposed photoresist layer to expose the seed metal wire layer;

electroplating the seed metal wire layer to a predetermined thickness to form a metal wire layer; and

removing the residual photoresist layer.

2. The method of claim 1, wherein the scattering layer is a polymer light scattering film or a light scattering glass.

3. The method of claim 1, wherein the seed metal layer is made of a material selected from copper and alloys thereof.

4. The method of claim 1, wherein the metal line layer has an aspect ratio of 1:1 to 1:10 and a line width of 3 μm to 15 μm.

5. The method of claim 1, wherein the thickness is between about 10 microns and about 100 microns.

6. The method of claim 1, wherein the thickness is between 3 microns and 15 microns.

7. The method of claim 1, wherein the thickness is between 3 microns and 30 microns.

8. The method of claim 1, wherein the thickness is between 5 microns and 15 microns.

9. The method of claim 1, wherein the thickness is between 5 microns and 30 microns.

Technical Field

The present invention relates to a metal electroplating technique, and more particularly, to a method for fabricating a metal electroplating wire.

Background

With the rapid development of portable electronic devices, the miniaturization of components and the requirements of reducing the line width of circuit boards, improving the precision and reducing the power consumption make the high aspect ratio copper electroplating process become a remarkable technology.

Currently, in the copper electroplating process with high aspect ratio, the accuracy can reach the degree that the line width is between 1 micron and 15 microns, and the thickness is between 10 microns and 100 microns. However, in order to achieve such accuracy, it is necessary to perform exposure and development processes. In order to fabricate the copper wire with high aspect ratio, an ultra-thin seed copper metal layer is formed on the substrate, and then the process is performed by forming a photoresist layer, exposing and developing, electroplating, removing the photoresist layer, etching, and the like. However, these processes affect the resistance of the copper lines and thus the accuracy of the copper lines due to over-etching of the copper metal surface after electroplating in the final etching process.

Another method for fabricating a high aspect ratio conductive line is to use a lift-off photoresist layer/negative photoresist layer dual-layer photoresist technique, such as taiwan patent No. I658483, in which a lift-off photoresist process is used to form a seed circuit metal layer on a seed metal layer, and then a high aspect ratio metal circuit is electroplated from the seed circuit metal layer without an etching process. The process applies the double-layer photoresist technology, and the double-layer photoresist needs higher technical strength for exposure and development at the same time, and is difficult to manufacture.

Therefore, how to simplify the electroplating process, so that the electroplating process can be simpler and more precise, and the over-etching problem caused by etching after electroplating will not occur, becomes the development direction required by the current electroplating technology developers.

Disclosure of Invention

The present invention uses the manufactured metal wire seed layer as a mask and uses a scattering layer as an auxiliary layer for back exposure to solve the diffraction problem generated by exposure when the metal wire seed layer is used as a mask, so as to accurately manufacture the structure required by negative photoresist exposure.

The invention aims to provide a method for manufacturing an electroplated metal wire, which comprises the following steps: forming a seed metal wire layer on a transparent substrate, wherein the wire of the seed metal wire layer is manufactured; forming a photoresist layer on the seed metal wire layer; providing a scattering layer on the other side of the transparent substrate; using the seed metal wire layer as a mask layer to perform scattering type exposure on the photoresist layer through the scattering layer; removing the unexposed photoresist layer to expose the seed metal wire layer; electroplating the seed metal wire layer to a predetermined thickness to form a metal wire layer; and removing the residual photoresist layer.

In some embodiments, the scattering layer employs a polymeric light scattering film or light scattering glass.

In some embodiments, the material of the seed metal layer is selected from copper metal or alloys thereof.

In some embodiments, the metal line layer has an aspect ratio of 1:1 to 1:10 and a line width of 3 to 15 microns.

In some embodiments, the thickness is between 10 microns and 100 microns.

In some embodiments, the thickness is between 3 microns to 15 microns.

In some embodiments, the thickness is between 3 microns to 30 microns.

In some embodiments, the thickness is between 5 microns to 15 microns.

In some embodiments, the thickness is between 5 microns to 30 microns.

In order to make the objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

FIG. 1 is a method for fabricating a plated metal wire according to the present invention;

FIGS. 2A-2L illustrate an embodiment of a process flow for forming a plated metal line of the present invention;

FIGS. 3A-3K illustrate another embodiment of a process flow for electroplating metal lines according to the present invention.

Symbolic illustration in the drawings:

10 a transparent substrate;

20 seed metal layers;

21 a seed metal wire layer;

29 a metal wiring layer;

30. 31 a photoresist layer;

40. 41, 42 photoresist layer;

70 mask;

50 a scattering layer;

80. 81 ultraviolet light;

s101 to S107.

Detailed Description

According to the embodiment of the invention, the manufactured metal wire seed layer is used as a photomask, and a scattering layer is used as an auxiliary layer for back exposure, so that the diffraction problem generated by exposure when the metal wire seed layer is used as the photomask is solved, the structure required by negative photoresist exposure can be accurately manufactured, the manufacturing process is simple and easy to implement, the cost is low, and the yield of the high-aspect-ratio electroplating process is greatly improved.

Referring to fig. 1, a method for fabricating a plated metal wire according to an embodiment of the present invention, referring to fig. 2A-2L and fig. 3A-3K, includes:

step S101: a seed metal wire layer is formed on a transparent substrate, and the wires of the seed metal wire layer are manufactured. There are two methods for fabricating the seed metal conductor layer in this step, one of which is to use exposure, development and etching (fig. 2A-2F); the second is to use Lift-off photoresist (Lift-off) (FIG. 3A-3E); both techniques are applicable.

FIGS. 2A-2F are schematic cross-sectional views illustrating a process for forming a conductive line of a seed metal layer by using an exposure, development and etching technique. Fig. 2A is a schematic cross-sectional view of a seed metal layer 20 formed on a transparent substrate 10. The method for forming the seed metal layer 20 can adopt a sputtering method or a spraying method to gradually form the seed metal layer 20 with the thickness of 1.5 μm to 20 μm on the transparent substrate 10; the transparent substrate 10 may be a glass substrate or a plastic substrate. Fig. 2B illustrates forming a photoresist layer 30 on the seed metal layer 20, wherein the photoresist layer 30 may be a positive photoresist or a negative photoresist, and the thickness may be 15 μm to 20 μm, and the photoresist layer may be formed by spin coating or spraying. FIG. 2C illustrates a photo mask 70 used to expose the photoresist layer 30 with UV light 80; the mask 70 is a mask with a patterned conductive line. In FIG. 2D, the photoresist layer 30 is developed, and the photoresist layer 31 is left to prevent the seed metal layer 20 from being etched. Fig. 2E is a schematic cross-sectional view after etching, and it can be seen that the seed metal layer not covered by the photoresist layer 31 has been etched away, and the seed metal layer 20 only leaves the seed metal wire layer 21. FIG. 2F shows the seed metal wire layer 21 on the transparent substrate 10 after removing the remaining photoresist layer 31.

The seed metal layer may be made of copper-based metal or alloy.

FIGS. 3A-3E illustrate cross-sectional views of a process for forming a conductive line of a seed metal layer by exposure, development and photoresist stripping. Fig. 3A illustrates a photoresist layer 30 formed on a transparent substrate 10, wherein the photoresist layer 30 may be a positive photoresist or a negative photoresist, and the thickness may be 15 μm to 20 μm, and the photoresist layer may be formed by spin coating or spraying. FIG. 3B illustrates a photo-mask 70 used to expose the photoresist layer 30 with UV light 80; the mask 70 is a mask with a patterned conductive line. In FIG. 3C, the photoresist layer 30 is developed, and the remaining photoresist layer 31 is lifted off the seed metal layer 20, i.e., the remaining photoresist layer 31 is a lift-off photoresist layer. FIG. 3D shows a seed metal layer 20 formed on the transparent substrate 10 with the photoresist layer 31; it can be seen that a portion of the seed metal layer 20 of this step is formed on the photoresist layer 31; the seed metal layer 20 may be formed by evaporation or spraying. Fig. 3E shows that after the residual photoresist layer 31 is removed, the portion of the seed metal layer 20 on the photoresist layer 31 is also removed, leaving the seed metal wiring layer 21 on the transparent substrate 10.

Step S102: a photoresist layer is formed on the seed metal line layer. As shown in fig. 2G and fig. 3F, the photoresist layer 40 is fully spread and covers the seed metal line layer 21. The thickness of the photoresist layer 40 can be determined according to the thickness of the metal wiring layer to be formed. For example, in order to form a metal wiring layer of 50-100 μm, the thickness of the photoresist layer 40 is not less than 50-100 μm.

Step S103: a scattering layer is provided on the other side of the transparent substrate. As shown in fig. 2H and fig. 3G, the light scattering layer 50 can scatter light, so that the problem of light diffraction in the next step can be solved.

Step S104: the seed metal wire layer is used as a mask layer to perform a scattering exposure on the photoresist layer through the scattering layer. As shown in fig. 2I and fig. 3H, due to the scattering layer 50, the ultraviolet light 80 in the original collimated state enters the scattering layer 50 and is scattered into the scattered ultraviolet light 81, and after passing through the transparent substrate 10, the diffraction problem of the ultraviolet light 80 in the original collimated state caused by the slit is solved at the edge of the seed metal wire layer 21, thereby generating the desired exposure result of the present invention. Therefore, the resolution of the metal wires applied in the present invention is relatively high, the gaps between the wires are very small, the line width is between 1 μm and 300 μm, and the pitch may be as small as 10 μm or even smaller. Such a small gap between the conductive lines will cause diffraction of light.

Step S105: removing the unexposed photoresist layer to expose the seed metal line layer. As shown in fig. 2J and fig. 3H, after the seed metal wire layer 21 is developed, the photoresist layer 41 (negative photoresist) thereon is not exposed, and can be removed by the developer to leave the exposed photoresist layer 42; the shape of the space above the seed metal wire layer 21 is the shape of the metal wire layer to be electroplated according to the present invention.

Step S106: electroplating the seed metal conductor layer to a predetermined thickness. As shown in fig. 2K and 3I, since the space above the seed metal wire layer 21 is limited by the exposed photoresist layer 42, electroplating the seed metal wire layer 21 can produce the metal wire layer 29 desired in the present invention. Wherein, the electroplated metal can be the same as or different from the seed metal wire layer. Preferably, the metal is the same as that of the seed metal wiring layer.

Step S107: removing the residual photoresist layer. As shown in fig. 2L and fig. 3J, the remaining exposed photoresist layer 42 is removed, so as to complete the metal wiring layer 29 of the present invention. Therefore, the electroplating process does not need to carry out an etching process, so that the problem of uneven impedance caused by damage to the surface of the electroplated metal due to over etching is solved.

The scattering layer may be a polymer light scattering film or light scattering glass.

Wherein, the aspect ratio of the metal wire layer is between 1:1 and 1:10, the line width is between 3 microns and 15 microns, and the thickness is between 10 microns and 100 microns, or between 3 microns and 15 microns, or between 3 microns and-30 microns, or between 5 microns and 15 microns, or between 5 microns and 30 microns.

The transparent substrate 11 may be a PET substrate (Polyethylene terephthalate, PET for short), a COP substrate, a PC substrate, a CPI substrate, a glass substrate, a Polyvinyl Butyral Resin (PVB) substrate, or the like. The light transmittance of the transparent substrate 10 in the visible light band is greater than 80%.

The negative resist used in the resist of the present invention can be a high resolution negative resist. The material of the photoresist layer mainly comprises a high molecular Resin (Resin), a Photo initiator (Photo initiator), a Monomer (Monomer), a Solvent (Solvent) and Additives (Additives).

Wherein in the material of the photoresist layer, the function of the polymer Resin (Resin) is adhesiveness, developability, pigment dispersibility, fluidity, heat resistance, chemical resistance, resolving power; the function of a Photo initiator (Photo initiator) is photosensitive property and resolving power; the Monomer functions in adhesion, developability, and resolution; the function of the Solvent (Solvent) is viscosity and coating properties; the Additives (Additives) function in terms of coatability, leveling and foamability.

The polymer Resin (Resin) may be a polymer or copolymer containing a carboxylic acid group (COOH), such as Acrylic Resin, acryl-Epoxy Resin, acryl-Melamine Resin, acryl-Styrene Resin, phenol-phenol Aldehyde Resin, or any mixture thereof, but not limited thereto. The weight percentage of the resin in the photoresist may range from 0.1% to 99%.

The Monomer can be divided into water-insoluble and water-soluble monomers, wherein the water-insoluble Monomer can be penterythritol triacrylate, trimethyletherpropane trimethacrylate, tri, di-ethanol isocyanate triacrylate, di, trimethylolpropane tetraacrylate, diisopentaerythritol pentaacrylate, and tetraacetate tetraol; hexa-acetic acid dihexyl tetrol, hexa-acetic acid diisoamyl tetrol, or polyfunctional monomers, dendritic/clustered acrylate oligomers, clustered polyether acrylate, and urethane. The water-soluble monomer can be polyoxyethylene (EO) base and Polyoxypropylene (PO) monomer; for example, the following are: di- (di-oxyethylene-oxy-ethylene) vinyl acrylate, pentadecyloxyethylene trimethylolpropane triacrylate, triacontoxyethylene di, di-p-phenomenol diacrylate, thirty oxyethylene di, di-p-phenomenol dimethacrylates, eicosoxyethylene trimethylolpropane triacrylate, pentadecoxyethylene trimethylolpropane triacrylate, pentadecyloxyethylene monomethylene methacrylate monomethacrylate, bis-hundred-oxyethylene diacrylate, tetra-hundred-oxyethylene-diacrylate-unitary acrylate, tetra-hundred-oxyethylene dimethacrylate, hexa-hundred-oxyethylene diacrylate, hexa-hundred-oxyethylene dimethacrylate, polyoxypropylene monomethacrylate. It is of course also possible to add two or more monomers (monomers) to mix them to form the comonomer (co-monomer). The weight percentage of monomer or co-monomer in the photoresist may range from 0.1% to 99%.

The photoinitiator (Photo initiator) may be selected from any mixture of the above photoinitiators, such as an acetophenone-based compound (acetophenone), a Benzophenone-based compound (Benzophenone), a bisimidazole-based compound (bis _ imidazole), a Benzoin-based compound (Benzoin), a Benzil-based compound (Benzil), an α -aminoketone-based compound (α -aminoketone), an acylphosphine oxide-based compound (acylphosphine oxide), or a benzoylformate-based compound, but is not limited thereto. The weight percentage of the photoinitiator in the photoresist may range from 0.1 to 10%.

The Solvent (Solvent) may be ethylene glycol propyl ether (ethylene glycol monopropylether), diethylene glycol dimethyl ether (di-ethylene glycol dimethyl ether), tetrahydrofuran, ethylene glycol methyl ether (ethylene glycol monomethylether), ethylene glycol ethyl ether (ethylene glycol monoethylether), diethylene glycol monomethyl ether (di-ethylene glycol mono-methyl ether), diethylene glycol monoethyl ether (di-ethylene glycol mono-ethyl ether), diethylene glycol monobutyl ether (di-ethylene glycol mono-butyl ether), propylene glycol methyl ether acetate (propylene glycol mono-methyl ether acetate), propylene glycol ethyl ether acetate (propylene glycol mono-ethyl ether acetate), propylene glycol propyl ether (propylene glycol propyl ether acetate (propylene glycol ether acetate), propionic acid acetate (propionic acid acetate, propionic acid, etc., but not limited to these solvents. The solvent may be present in the photoresist in an amount ranging from 0.1% to 99% by weight.

The additive is typically a pigment dispersant, which is an essential ingredient for a pigment-containing resist, typically a nonionic surfactant, such as: solsperse39000, Solsperse21000, the weight percent of this dispersant in the photoresist can range from 0.1 to 5%.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made without departing from the spirit and scope of the invention as defined by the appended claims.