# US 8,784,636 B2 · Plating apparatus and plating method

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- Number: US 8,784,636 B2
- Document ID: US8784636B2
- Status: Granted
- Kind: B2
- Application number: 12/314,080
- Filed: 2008-12-03
- Published: 2009-06-04
- Granted: 2014-07-22
- Earliest claimed: 2007-12-04
- Assignees: Ebara Corporation
- Applicants: Mizuki Nagai; Nobutoshi Saito; Fumio Kuriyama; Akira Fukunaga
- Inventors: Mizuki Nagai; Nobutoshi Saito; Fumio Kuriyama; Akira Fukunaga
- Web page: https://patentgrep.com/patent/US8784636B2

## CPC

- C25D 5/08: Electroplating with moving electrolyte e.g. jet electroplating {(using locally applied jets of electrolyte C25D5/026)}
- C23C 14/046: {Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates}
- C23C 14/16: on metallic substrates or on substrates of boron or silicon
- C23C 14/584: {Non-reactive treatment}
- C25D 5/003: {Electroplating using gases, e.g. pressure influence}
- C25D 5/022: {using masking means}
- C25D 5/10: Electroplating with more than one layer of the same or of different metals (for bearings C25D7/10)
- C25D 5/611: {Smooth layers}
- C25D 7/123: {Semiconductors first coated with a seed layer or a conductive layer}
- C25D 17/001: {Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells}
- C25D 21/10: Agitating of electrolytes; Moving of racks
- H05K 3/423: {characterised by electroplating method}
- H10P 14/47: Electrolytic deposition, i.e. electroplating; Electroless plating
- H10W 20/036: {the barrier, adhesion or liner layers being within a main fill metal}
- H10W 20/037: {the barrier, adhesion or liner layers being on top of a main fill metal}
- H10W 20/057: {by selectively depositing, e.g. by using selective CVD or plating}
- H05K 3/108: {by semi-additive methods; masks therefor (characterised by metallic etch mask H05K3/062; electroplating methods or apparatus H05K3/241)}
- H05K 2201/09563: Metal filled via
- H05K 2203/1476: Same or similar kind of process performed in phases, e.g. coarse patterning followed by fine patterning
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A method can form a conductive structure, which is useful for three-dimensional packaging with via plugs, in a shorter time by shortening the conventional long plating time that is an impediment to the practical use of electroplating. The method includes forming a conductive film on an entire surface, including interior surfaces of via holes, of a substrate having the via holes formed in the surface; forming a resist pattern at a predetermined position on the conductive film; carrying out first electroplating under first plating conditions, using the conductive film as a feeding layer, thereby filling a first plated film into the via holes; and carrying out second electroplating under second plating conditions, using the conductive film and the first plated film as a feeding layer, thereby allowing a second plated film to grow on the conductive film and the first plated film, both exposed in the resist openings of the resist pattern.

## Claims

### Claim 1

A method for forming a conductive structure having via plugs for use in three-dimensional packaging, comprising:
preparing a substrate having upwardly-open via holes each having a diameter in a range of 10 μm to 20 μm and a depth of 70 μm to 150 μm, a conductive film formed on an entire surface of the substrate, including interior surfaces of the via holes, and a resist pattern formed at a predetermined position on the conductive film;
carrying out first electroplating under first plating conditions, using the conductive film as a feeding layer, so as to fill the via holes with a first plated film to form the via plugs, the first electroplating including immersing the substrate in a first plating solution containing an additive for suppressing plating growth while stirring the first plating solution to suppress the plating growth at entrances to the via holes, an electric current in the first plating conditions is one of a constant current, a stepwise current, or a pulse current;
after filling the via holes with the first plated film, carrying out second electroplating under second plating conditions, using the conductive film and the first plated film as a feeding layer, by immersing the substrate in a second plating solution so as to grow a second plated film on the first plated film and on a portion of the conductive film exposed in resist openings of the resist pattern until the second plated film having a flat surface is formed in the resist openings to thereby fill the via holes and resist openings without defects, the first plated film and the second plated film being composed of the same metal, an average current value in the second plating conditions being higher than an average current value in the first plating conditions; and
during the second electroplating, supplying a nitrogen gas into the second plating solution facing a to-be-plated surface of the substrate.

### Claim 2 (depends on 1)

The method for forming a conductive structure according to claim 1, wherein a height of the resist pattern is 5 μm to 100 μm.

### Claim 3 (depends on 1)

The method for forming a conductive structure according to claim 1, wherein each of the first plated film and the second plated film are composed of copper or a copper alloy.

### Claim 4 (depends on 1)

The method for forming a conductive structure according to claim 1, wherein the second electroplating is conducted until the second plated film grows to a point halfway between the surface of the first plated film and a top of the resist pattern, and then third electroplating is carried out under third plating conditions to so that a third plated film grows on the second plated film.

### Claim 5 (depends on 4)

The method for forming a conductive structure according to claim 4, wherein the third plated film is composed of a metal different from a metal of the first plated film and a metal of the second plated film.

### Claim 6 (depends on 1)

The method for forming a conductive structure according to claim 1, wherein the first plating conditions of the first electroplating includes an average current density in a range of 0.1 mA/cm2 to 5.0 mA/cm2.

### Claim 7 (depends on 6)

The method for forming a conductive structure according to claim 6, wherein the second plating conditions of the second electroplating includes an average current density at least twice as large as an average current density of the first plating conditions of the first electroplating.

### Claim 8 (depends on 1)

The method for forming a conductive structure according to claim 1, wherein the second plating conditions of the second electroplating includes an average current density at least twice as large as an average current density of the first plating conditions of the first electroplating.

### Claim 9 (depends on 1)

The method for forming a conductive structure according to claim 1, wherein the first electroplating under the first plating conditions is switched to the second electroplating under the second plating conditions when a surface of the first plated film filling each of the via holes has a concave shape to thereby prevent the surface of the first plated film in each of the via holes from achieving a convex shape with a raised central portion.

### Claim 10 (depends on 1)

The method for forming a conductive structure according to claim 1, wherein the additive of the first plating solution includes at least one of a sulfur compound, a polymer, and a nitrogen compound.

### Claim 11 (depends on 1)

The method for forming a conductive structure according to claim 1, wherein a composition of the second plating solution is different than a composition of the first plating solution.

### Claim 12

A method for forming a conductive structure having via plugs for use in three-dimensional packaging, comprising:
preparing a substrate having upwardly-open via holes each having a diameter in a range of 10 μm to 20 μm and a depth of 70 μm to 150 μm, a conductive film formed on an entire surface of the substrate, including interior surfaces of the via holes, and a resist pattern formed at a predetermined position on the conductive film;
carrying out first electroplating under first plating conditions, using the conductive film as a feeding layer, so as to fill the via holes with a first plated film to form the via plugs, the first electroplating including immersing the substrate in a first plating solution containing an additive for suppressing plating growth while stirring the first plating solution to suppress the plating growth at entrances to the via holes, an electric current in the first plating conditions is one of a constant current, a stepwise current, or a pulse current;
during the first electroplating, supplying a nitrogen gas into the first plating solution facing a to-be-plated surface of the substrate; and
after filling the via holes with the first plated film, carrying out second electroplating under second plating conditions, using the conductive film and the first plated film as a feeding layer, by immersing the substrate in a second plating solution so as to grow a second plated film on the first plated film and on a portion of the conductive film exposed in resist openings of the resist pattern until the second plated film having a flat surface is formed in the resist openings to thereby fill the via holes and resist openings without defects, the first plated film and the second plated film being composed of the same metal, an average current value in the second plating conditions being higher than an average current value in the first plating conditions.

### Claim 13 (depends on 12)

The method for forming a conductive structure according to claim 12, further comprising, during the second electroplating, supplying a gas into the second plating solution facing the to-be-plated surface of the substrate.

### Claim 14 (depends on 13)

The method for forming a conductive structure according to claim 13, wherein the gas supplied into the second plating solution facing the to-be-plated surface of the substrate is nitrogen gas.

### Claim 15 (depends on 12)

The method for forming a conductive structure according to claim 12, wherein a composition of the second plating solution is different than a composition of the first plating solution.