CN115404479A - Chemical solution for etching treatment - Google Patents

Chemical solution for etching treatment Download PDF

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Publication number
CN115404479A
CN115404479A CN202210207401.9A CN202210207401A CN115404479A CN 115404479 A CN115404479 A CN 115404479A CN 202210207401 A CN202210207401 A CN 202210207401A CN 115404479 A CN115404479 A CN 115404479A
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CN
China
Prior art keywords
copper
chemical solution
thin film
acid
substrate
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CN202210207401.9A
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Chinese (zh)
Inventor
吴宇耕
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Tokyo Ohka Kogyo Co Ltd
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Tokyo Ohka Kogyo Co Ltd
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Publication of CN115404479A publication Critical patent/CN115404479A/en
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/10—Etching compositions
    • C23F1/14—Aqueous compositions
    • C23F1/16—Acidic compositions
    • C23F1/18—Acidic compositions for etching copper or alloys thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
    • H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
    • H01L21/32134—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by liquid etching only

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Computer Hardware Design (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • ing And Chemical Polishing (AREA)
  • Weting (AREA)

Abstract

The invention provides a chemical solution for etching treatment, which can well etch a copper thin film as a seed layer and prevent excessive etching of a copper-plated shaped object, and provides a method for manufacturing a substrate with the copper-plated shaped object, which comprises etching by using the chemical solution. An oxidizing substance (A) and water (W) are contained in a chemical solution for etching a target object obtained by stacking a substrate, a copper thin film formed by a method other than plating, and a copper-plated shaped object in this order in the thickness direction of the substrate, a combination of an oxoacid (A1 a) and a peroxide (A1 b) or a peracid (A2) is used as the oxidizing substance (A), and at least one of acetic acid as the oxoacid (A1 a) and peracetic acid as the peracid (A2) is contained in the oxidizing substance (A).

Description

Chemical solution for etching treatment
Technical Field
The present invention relates to a chemical solution for etching a target object obtained by stacking a substrate, a copper thin film, and a copper-plated shaped object in this order in the thickness direction of the substrate, and a method for manufacturing a substrate having a copper-plated shaped object using the chemical solution.
Background
In response to the increase in the functions and the reduction in the sizes of semiconductor devices, flip chip mounting is widely used as a method for mounting and bonding a semiconductor device on a substrate. In flip chip mounting, a plurality of electrodes (bumps) through which a semiconductor device is connected to a substrate are formed on a seed layer mainly composed of copper on the substrate.
As a method for manufacturing a bumped wiring board applicable to flip-chip mounting, the following methods have been proposed: after a resist film serving as a mold for forming an electrode is provided on a seed layer on a substrate formed by electroless plating, the substrate is subjected to electroplating to form a stud bump made of copper in the mold, and then the resist film and the seed layer exposed on the surface of the substrate are removed by etching (see patent document 1).
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2018-157051
Disclosure of Invention
Technical problems to be solved by the invention
However, in patent document 1, removal of a copper thin film as a seed layer by etching after removing a mold for plating is not sufficiently studied. In the method described in patent document 1, when the seed layer is etched by a conventionally known method, not only the copper thin film as the seed layer but also a copper-plated shaped article such as a copper terminal formed by plating is etched in a large amount.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a chemical solution for etching treatment which can prevent excessive etching of a copper-plated shaped article while satisfactorily etching a copper thin film as a seed layer, and a method for manufacturing a substrate having a copper-plated shaped article, which includes etching using the chemical solution.
Means for solving the above technical problems
The present inventors have found that the above technical problems can be solved by the following means: the present inventors have completed the present invention by including an oxidizing substance (a) and water (W) in a chemical solution for etching a target object obtained by stacking a substrate, a copper thin film formed by a method other than plating, and a copper-plated shaped object in this order in the thickness direction of the substrate, using a combination of an oxoacid (A1 a) and a peroxide (A1 b) or a peracid (A2) as the oxidizing substance (a), and including at least one of acetic acid as the oxoacid (A1 a) and peracetic acid as the peracid (A2) in the oxidizing substance (a).
The invention according to claim 1 is a chemical solution for etching an object to be processed in which a substrate, a copper thin film, and a copper-plated shaped article are stacked in this order in the thickness direction of the substrate,
the chemical liquid contains an oxidizing substance (A) and water (W),
the oxidizing substance (A) comprises a combination of an oxo acid (A1 a) and a peroxide (A1 b) or comprises a peracid (A2),
the oxidizing substance (A) contains at least one of acetic acid as an oxoacid (A1 a) and peracetic acid as a peracid (A2),
the copper thin film covers at least a part of the main surface of the substrate,
the copper thin film is a film formed by a method other than plating,
the copper-plated shaped article is formed by plating using a copper thin film as a seed layer.
A second aspect of the present invention is a method for manufacturing a substrate having a copper-plated shaped object, including:
forming a copper thin film on a substrate;
forming a mold for plating on the copper thin film;
a step of plating copper on a substrate provided with a mold and forming a copper-plated molded article in the mold;
a step of removing the mold after the copper-plated molded article is formed;
and (3) etching the copper thin film using the chemical solution according to claim 1 after the mold is peeled.
Effects of the invention
According to the present invention, it is possible to provide a chemical solution for etching treatment which can prevent excessive etching of a copper-plated shaped article while satisfactorily etching a copper thin film as a seed layer, and a method for manufacturing a substrate having a copper-plated shaped article, which includes etching using the chemical solution.
Detailed Description
The present invention is not limited to the embodiments described below, and can be implemented by making appropriate changes within the scope of the object of the present invention.
Medicinal liquid
The chemical solution is used for etching an object to be processed in which a substrate, a copper thin film, and a copper-plated molded article are stacked in this order in the thickness direction of the substrate.
The copper thin film covers at least a part of the main surface of the substrate. The copper thin film is a film formed by a method other than plating. The copper-plated shaped article is formed by plating using the copper thin film as a seed layer.
By etching the object to be processed with a chemical solution described later, only a small amount of a copper-plated shaped object can be etched, and on the other hand, a large amount of a copper thin film formed by a method other than plating can be etched to a desired degree.
The chemical liquid contains an oxidizing substance (A) and water (W).
The oxidizing substance (A) comprises a combination of an oxo acid (A1 a) and a peroxide (A1 b) or comprises a peracid (A2). The oxidizing substance (a) contains at least one of acetic acid as the oxoacid (A1 a) and peracetic acid as the peracid (A2).
The chemical solution may contain any component such as the anticorrosive agent (B) or the surfactant (C).
The chemical solution may be a one-pack type composition containing the oxidizing substance (a) and water (W) and optionally containing any component. The chemical solution may be a multi-liquid type composition composed of 2 or more kinds of liquids having different compositions.
Examples of the case where the chemical solution is a multi-liquid type composition include:
1) A chemical solution comprising a1 st liquid containing an oxidizing substance (A) and water (W), and a2 nd liquid containing an anticorrosive agent (B);
2) A chemical solution comprising a1 st liquid containing an oxidizing substance (A) and water (W), and a2 nd liquid containing a surfactant (C);
3) A chemical solution comprising a1 st liquid containing an oxidizing substance (A) and water (W), and a2 nd liquid containing an anticorrosive agent (B) and a surfactant (C);
4) A chemical solution composed of A1 st liquid containing an oxoacid (A1 a) and water (W), and a2 nd liquid containing a peroxide (A1 b);
5) A chemical solution comprising A1 st liquid containing acetic acid as an oxo acid (A1 a) and water (W), and a2 nd liquid containing a peroxide (A1 b);
6) A chemical liquid comprising A1 st liquid containing acetic acid as an oxoacid (A1 a) and water (W), a2 nd liquid containing an oxoacid other than acetic acid as an oxoacid (A1 a) and water (W), and a 3 rd liquid containing a peroxide (A1 b);
7) A chemical solution comprising A1 st liquid containing an oxoacid (A1 a) and water (W), a2 nd liquid containing a peroxide (A1B), and a 3 rd liquid containing an anticorrosive agent (B);
8) A chemical solution composed of A1 st liquid containing an oxoacid (A1 a) and water (W), a2 nd liquid containing a peroxide (A1 b), and a 3 rd liquid containing a surfactant (C);
9) A chemical solution comprising A1 st liquid containing an oxoacid (A1 a) and water (W), a2 nd liquid containing a peroxide (A1B), and a 3 rd liquid containing an anticorrosive agent (B) and a surfactant (C);
10 A chemical solution comprising A1 st liquid containing acetic acid as an oxoacid (A1 a) and water (W), a2 nd liquid containing a peroxide (A1B), and a 3 rd liquid containing an anticorrosive agent (B);
11 A chemical solution comprising A1 st liquid containing acetic acid as an oxyacid (A1 a) and water (W), a2 nd liquid containing a peroxide (A1 b), and a 3 rd liquid containing a surfactant (C);
12 A chemical solution comprising A1 st liquid containing acetic acid as an oxoacid (A1 a) and water (W), a2 nd liquid containing a peroxide (A1B), and a 3 rd liquid containing an anticorrosive agent (B) and a surfactant (C);
13 A chemical liquid comprising A1 st liquid containing acetic acid as an oxoacid (A1 a) and water (W), a2 nd liquid containing an oxoacid other than acetic acid as an oxoacid (A1 a) and water (W), a 3 rd liquid containing a peroxide (A1B), and a 4 th liquid containing an anticorrosive agent (B);
14 A chemical liquid comprising A1 st liquid containing acetic acid as an oxoacid (A1 a) and water (W), a2 nd liquid containing an oxoacid other than acetic acid as an oxoacid (A1 a) and water (W), a 3 rd liquid containing a peroxide (A1 b), and a 4 th liquid containing a surfactant (C);
15 A chemical liquid comprising A1 st liquid containing acetic acid as an oxoacid (A1 a) and water (W), a2 nd liquid containing an oxoacid other than acetic acid as the oxoacid (A1 a) and water (W), a 3 rd liquid containing a peroxide (A1B), and a 4 th liquid containing an anticorrosive agent (B) and a surfactant (C);
16 A chemical solution comprising a1 st liquid containing a peracid (A2) and water (W) and A2 nd liquid containing an anticorrosive agent (B);
17 A chemical solution comprising a1 st liquid containing a peracid (A2) and water (W), and A2 nd liquid containing a surfactant (C);
18 A chemical solution comprising a first liquid 1 containing a peracid A2 and water W and a second liquid 2 containing an anticorrosive agent B and a surfactant C;
19 A chemical solution comprising a1 st liquid containing peracetic acid as a peracid (A2) and water (W), and A2 nd liquid containing an anticorrosive agent (B);
20 A chemical solution comprising a1 st liquid containing peracetic acid as a peracid (A2) and water (W), and A2 nd liquid containing a surfactant (C);
21 A chemical solution comprising a first liquid 1 containing peracetic acid as a peracid (A2) and water (W), and a second liquid 2 containing an anticorrosive agent (B) and a surfactant (C);
22 A chemical solution comprising a1 st liquid containing peracetic acid as the peracid (A2) and water (W), A2 nd liquid containing peracid other than peracetic acid as the peracid (A2) and water (W), and a 3 rd liquid containing an anticorrosive agent (B);
23 A chemical solution comprising a1 st liquid containing peracetic acid as the peracid (A2) and water (W), A2 nd liquid containing peracid other than peracetic acid as the peracid (A2) and water (W), and a 3 rd liquid containing a surfactant (C);
24 A liquid chemical comprising a first liquid 1 containing peracetic acid as the peracid (A2) and water (W), a second liquid 2 containing a peracid other than peracetic acid as the peracid (A2) and water (W), and a third liquid 3 containing an anticorrosive agent (B) and a surfactant (C).
The chemical solution of the multi-liquid type composition is not limited to the examples of 1) to 24) described above.
In the case of a chemical solution as a multi-liquid type composition, when the anticorrosive agent (B) and the surfactant (C) are liquid, the solution containing the anticorrosive agent (B) and/or the surfactant (C) may not contain a solvent. As the solvent, water (W) can be used. As the solvent, various organic solvents can be used as long as the desired effects are not impaired.
In view of the fact that only a small amount of a copper-plated shaped article is etched and that on the other hand, a large amount of a copper thin film formed by a method other than plating is etched to a desired extent is etched, and that the preparation and use of a chemical solution are easy, it is preferable that the chemical solution of the multi-liquid composition is a chemical solution composed of A1 st solution containing acetic acid and water (W) as the oxoacid (A1 a) and a2 nd solution containing the peroxide (A1 b).
The 1 st liquid containing acetic acid as the oxoacid (A1 a) and water (W) may contain an oxoacid other than acetic acid.
The 1 st liquid containing acetic acid as the oxoacid (A1 a) and water (W), and the 2 nd liquid containing the peroxide (A1B) may also contain an anticorrosive agent (B) and/or a surfactant (C), respectively.
When the chemical solution is a multi-liquid type composition, the object to be processed is etched using a mixed solution obtained by mixing 2 or more kinds of liquids constituting the multi-liquid type composition.
Hereinafter, the object to be processed for etching with the chemical solution and essential or arbitrary components contained in the chemical solution will be described.
< object to be treated >
As described above, as an object to be etched by the chemical solution, a substrate, a copper thin film, and a copper-plated molded article can be used, which are stacked in this order in the thickness direction of the substrate.
The copper thin film covers at least a part of the main surface of the substrate. The copper thin film is a film formed by a method other than plating. The copper-plated shaped article is a shaped article formed by plating using a thin film as a seed layer.
As the substrate constituting the object to be processed, a substrate suitable for a mounting method such as flip chip mounting can be used without particular limitation. As a material of a surface of the substrate covered with a copper thin film described later, for example, a metal used as a material of an under bump metal layer, which has been conventionally used in combination with a copper thin film, can be used. Examples of the metal used as a material of the under bump metal layer include titanium, a titanium-tungsten alloy, and a titanium-copper alloy. As a material of another layer in the substrate in contact with the layer corresponding to the under bump metal layer, for example, a semiconductor such as silicon can be used. That is, as a substrate constituting the object to be processed, a semiconductor substrate having a layer corresponding to the under bump metal layer described above on at least one main surface can be preferably used.
The copper thin film is formed by a method other than plating so as to cover at least a part of the main surface of the substrate. Examples of the method for forming a copper thin film include Physical Vapor Deposition (PVD), ion plating, and sputtering. Among these methods, physical vapor deposition is preferred because a copper thin film which is easily etched by a chemical solution can be easily formed.
The thickness of the copper thin film is not particularly limited. The thickness of the copper thin film is typically preferably 50nm to 300nm, more preferably 70nm to 250nm, and still more preferably 100nm to 200 nm.
The copper-plated shaped article is formed by plating using a copper thin film as a seed layer. The method for producing the copper-plated shaped article is not particularly limited. Typically, a mold having a void corresponding to the shape of a copper-plated shaped object is formed at a position where the copper-plated shaped object is to be formed on a copper thin film serving as a seed layer, and then the substrate provided with the mold is subjected to copper plating by a known method to form the copper-plated shaped object. In addition, the copper thin film serving as a seed layer is exposed in the gap.
The method of forming the mold is not particularly limited. Typically, the mold can be formed by a general photolithography method using the photosensitive composition.
The photosensitive composition is not particularly limited as long as it can form a film having durability against the plating solution. The photosensitive composition may be a negative composition that is cured by exposure to light and is insoluble in a developer, or may be a positive composition that is solubilized in a developer by exposure to light.
After the copper plating is performed as described above, the mold is peeled from the substrate by a known method corresponding to the type of the composition used to form the mold.
The copper-plated shaped object is typically a bump (electrode) such as a metal pillar, or a copper wiring or a copper rewiring. The shape of the copper-plated shaped article is not particularly limited, and in the case of a rewiring layer, the height of the copper-plated shaped article in the thickness direction of the substrate is preferably 2 μm to 6 μm, and more preferably 2.5 μm to 4 μm, and in the case of a bump, the height of the copper-plated shaped article in the thickness direction of the substrate is preferably 10 μm to 300 μm, and more preferably 20 μm to 70 μm.
< oxidizing substance (A) >
The oxidizing substance (A) comprises a combination of an oxo acid (A1 a) and a peroxide (A1 b) or comprises a peracid (A2).
The oxidizing substance (a) must contain at least one of acetic acid as the oxoacid (A1 a) and peracetic acid as the peracid (A2).
By containing the oxidizing substance (a), the chemical solution can etch only a small amount of the copper-plated shaped article, while etching a large amount of the copper thin film formed by a method other than plating to a desired extent.
[ Oxoacetic acid (A1 a) ]
As mentioned above, the oxo acid (A1 a) must comprise acetic acid. The content of acetic acid in the chemical solution is not particularly limited as long as the desired effect is not impaired. The content of acetic acid in the chemical solution is preferably 0.001 to 5 mass%, more preferably 0.002 to 2 mass%, and still more preferably 0.003 to 1 mass%, based on the mass of the chemical solution.
The chemical solution may be a multi-liquid type of 2-liquid type or more as described later. When the chemical liquid is a multi-liquid type, the content of acetic acid in the chemical liquid is a ratio of the mass of acetic acid to the total mass of the plurality of liquids.
The oxoacid (A1 a) may contain only acetic acid, or may contain acetic acid and an oxoacid other than acetic acid. In the specification of the present application, the oxo acid (A1 a) is an oxo acid which does not belong to peroxides having a-O-bond. Examples of the oxo acid other than acetic acid include carboxylic acids other than acetic acid, halogenated oxo acids, silicic acid, nitrous acid, nitric acid, phosphorous acid, phosphoric acid, sulfurous acid, sulfuric acid, and sulfonic acids.
In addition, the oxo acid (A1 a) is a monobasic acid having 1 acid group in the molecule, not a polybasic acid having 2 or more acid groups in the molecule.
Specific examples of the carboxylic acids other than acetic acid include formic acid, propionic acid, butyric acid, valeric acid, caproic acid, benzoic acid, and lactic acid. Specific examples of the halogenated oxyacid include hypochlorous acid, chlorous acid, chloric acid, hypobromous acid, bromic acid and the like.
Among the above-mentioned oxyacids which can be used together with acetic acid, phosphoric acid (H) is preferable from the viewpoint of easy etching of a copper thin film formed by a method other than plating 3 PO 4 )。
The content of the oxoacid other than acetic acid in the chemical solution is not particularly limited as long as the desired effect is not impaired. The content of the oxoacids other than acetic acid in the chemical solution is preferably 0.1 mass% to 10 mass%, more preferably 0.2 mass% to 7 mass%, and still more preferably 0.5 mass% to 5 mass%, based on the mass of the chemical solution.
The chemical solution may be a multi-liquid type of 2-liquid type or more as described later. In the case where the chemical liquid is a multi-liquid type, the content of the oxoacid other than acetic acid in the chemical liquid is a ratio of the mass of the oxoacid other than acetic acid to the total mass of the plural liquid types.
[ peroxide (A1 b) ]
The peroxide (A1 b) is not particularly limited as long as it is a compound having an-O-bond. The peroxide may be a compound corresponding to a peracid (A2) described later. In the specification of the present application, when the chemical solution contains the oxo acid (A1 a) and also contains the peracid, the chemical solution contains the oxo acid (A1 a) and the peracid as the peroxide (A1 b).
Specific examples of the peroxide (A1 b) include inorganic peroxides such as hydrogen peroxide, lithium peroxide and potassium peroxide, organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, dimethyl dioxirane, acetone peroxide, methyl ethyl ketone peroxide and hexamethylene-triamine peroxide; peracids such as persulfuric acid, percarbonic acid, perphosphoric acid, hypoperchloric acid, hypoperbromic acid, hypoperiodic acid, and percarboxylic acid.
Examples of the percarboxylic acid include performic acid, perbenzoic acid, and m-chloroperbenzoic acid.
Among the peroxides (A1 b), hydrogen peroxide is preferable because it is inexpensive and easy to handle and can easily etch a copper thin film formed by a method other than plating using a chemical solution.
The content of the peroxide (A1 b) in the chemical solution is 5 mass% or less, preferably 1 mass% or less, based on the mass of the entire chemical solution.
[ peracid (A2) ]
The chemical solution may contain a peracid (A2) as the oxidizing substance (a). As described above, in the specification of the present application, when the chemical solution contains the oxoacid (A1 a) and further contains the peracid, the chemical solution contains the oxoacid (A1 a) and the peracid which is the peroxide (A1 b).
When the chemical solution contains the peracid (A2), the chemical solution contains peracetic acid as the peracid (A2). The content of peracetic acid in the chemical solution is not particularly limited within a range that does not impair the desired effects.
The content of peracetic acid in the chemical liquid is preferably 0.001 mass% or more and 5 mass% or less, more preferably 0.002 mass% or more and 2 mass% or less, and further preferably 0.003 mass% or more and 1 mass% or less, with respect to the mass of the chemical liquid.
The chemical solution may be a multi-liquid type of 2 or more liquids as described later. When the chemical liquid is a multi-liquid type, the content of peracetic acid in the chemical liquid is a ratio of the mass of peracetic acid to the total mass of the plurality of liquids.
The chemical solution may contain peracetic acid and a peracid other than peracetic acid as the peracid (A2). As the peracid other than peracetic acid, the same compound as the peracid described for the peroxide (A1 b) can be used.
Among peracids other than peracetic acid which can be used together with peracetic acid, perphosphoric acid is preferable in terms of easily etching a copper thin film formed by a method other than plating.
The content of peracid other than peracetic acid in the chemical solution is not particularly limited as long as the desired effect is not impaired. The content of peracid other than peracetic acid in the chemical solution is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.2% by mass or more and 7% by mass or less, and further preferably 0.5% by mass or more and 5% by mass or less, based on the mass of the chemical solution.
The chemical solution may be a multi-liquid type of 2 or more liquids as described later. When the chemical liquid is a multi-liquid type, the content of the peracid other than peracetic acid in the chemical liquid is the ratio of the mass of the peracid other than peracetic acid to the total mass of the plurality of liquids.
[ anticorrosive agent (B) ]
The chemical solution may also contain an anticorrosive agent (B). By including the anticorrosive agent (B) in the chemical solution, the copper thin film can be etched while suppressing an increase in the surface roughness of the copper-plated shaped article after etching. As the anticorrosive agent (B), a compound known to be used as an anticorrosive agent for copper can be used without particular limitation.
Preferable examples of the anticorrosive agent (B) include nitrogen-containing compounds selected from 1H-imidazoles, pyrazoles, thiazoles, triazoles, and guanidines. These can be used alone in 1 or more than 2.
Examples of the 1H-imidazole include 1H-imidazole, 2-methyl-1H-imidazole, 2-ethyl-1H-imidazole, 2-isopropyl-1H-imidazole, 2-propyl-1H-imidazole, 2-butyl-1H-imidazole, 4-methyl-1H-imidazole, 2, 4-dimethyl-1H-imidazole, 2-ethyl-4-methyl-1H-imidazole, 2-amino-1H-imidazole and 1H-benzimidazole-2-thiol (2-mercaptobenzimidazole).
Examples of the pyrazole include 3, 5-dimethylpyrazole, 3-methyl-5-pyrazolone, 3-amino-5-methylpyrazole, 3-amino-5-hydroxypyrazole and 3-amino-5-methylpyrazole.
Examples of the thiazole include 2-aminothiazole, 4, 5-dimethylthiazole, 2-amino-2-thiazoline, 2, 4-dimethylthiazole and 2-amino-4-methylthiazole.
Examples of the triazole include 1,2, 4-triazole, 3-amino-1, 2, 4-triazole, 4-amino-1, 2, 4-triazole, 1,2, 4-triazolo [1,5-a ] pyrimidine, 1,2, 3-triazolo [4,5-b ] pyridine, benzotriazole, and 5-methylbenzotriazole.
The guanidine may, for example, be guanidine, 1, 3-diphenylguanidine or 1- (o-tolyl) biguanide.
The content of the anticorrosive agent (B) in the chemical solution is not particularly limited within a range that does not impair the desired effects. The preferable range of the content of the anticorrosive agent (B) in the chemical solution is preferably 0.0001 to 10 mass%, more preferably 0.001 to 5 mass%, and still more preferably 0.01 to 1 mass% with respect to the mass of the chemical solution.
[ surfactant (C) ])
By including the surfactant (C) in the chemical solution, the wettability of the chemical solution to the material constituting the object to be treated such as a copper-plated molded article can be improved. As a result, even when the copper thin films are located in the vicinity of the lower portions of the plurality of copper-plated shaped objects adjacent to each other at the extremely close position, the chemical solution can favorably intrude into the gaps between the copper-plated shaped objects, and the copper thin films can favorably be etched.
The surfactant (C) is not particularly limited, and conventionally known surfactants can be used. Any of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants can be used as the surfactant (C).
As the nonionic surfactant, for example, alkylene oxide adducts of glycols having a carbon-carbon triple bond or alkylene oxide adducts of monoalcohols having a carbon-carbon triple bond are preferred.
The alkylene oxide adduct of a glycol having a carbon-carbon triple bond is preferably a nonionic surfactant represented by the following formula (c-1), for example.
HO-(R c6 -O) n1 -CR c3 R c4 -C≡C-CR c1 R c2 -(O-R c5 ) n2 -OH…(c-1)
In the formula (c-1), R c1 ～R c4 Each independently a linear or branched alkyl group having 1 to 6 carbon atoms. R c5 And R c6 Each independently a linear or branched alkylene chain having 2 to 4 carbon atoms. n1 and n2 are each independently an integer of 0 to 30 inclusive.
As R c1 ～R c4 Methyl, ethyl and isopropyl are preferred. As R c5 And R c6 Preferred are ethane-1, 2-diyl (ethylene), propane-1, 3-diyl, propane-1, 2-diyl and butane-1, 4-diyl. N1 and n2 are preferably integers of 0 to 16 inclusive.
Specific examples of the alkylene oxide adduct of a glycol having a carbon-carbon triple bond and the alkylene oxide adduct of a mono alcohol having a carbon-carbon triple bond include OLFINEEXP4200 manufactured by Nikken chemical industries, SURFYNOL104E, SURFYNOL104H, SURFYNOL104A, SURFYNOL104PA and SURFYNOL104PG-50 and the like "SURFYNOL104 series", and SURFYNOL420, SURFYNOL445, SURFYNOL465 and SURFYNOL485 and the like "SURFYNOL400 series", which are manufactured by air chemical industries. Among these, "SURFYNOL400 series" is preferable.
Examples of the anionic surfactant may include anionic surfactants represented by the following formula (c-2).
R c7 -SO 3 H…(c-2)
In the formula (c-2), R c7 Is a linear or branched alkyl group having 7 to 20 carbon atoms. The alkyl group may have a hydroxyl group and/or a carboxyl group, or may be interrupted by a phenylene group and/or an oxygen atom.
As R c7 The alkyl group is preferably a linear or branched alkyl group having 8 to 11 carbon atoms.
Specific examples of the anionic surfactant represented by the formula (c-2) include n-octane sulfonic acid, n-nonane sulfonic acid, n-decane sulfonic acid, and n-undecane sulfonic acid. Among them, n-octane sulfonic acid, n-nonane sulfonic acid and n-decane sulfonic acid are preferable.
The content of the surfactant (C) in the chemical solution is not particularly limited within a range that does not impair the desired effect. The preferable range of the content of the surfactant (C) in the chemical solution is preferably 0.0001 to 10% by mass, more preferably 0.001 to 5% by mass, and still more preferably 0.01 to 1% by mass, relative to the mass of the chemical solution.
[ chelating agent (D) ])
The chemical solution may contain a chelating agent (D). The chelating agent (D) is a compound not belonging to the above-mentioned oxo acid (A1 a) which is a monobasic acid having 1 acidic group in the molecule. The chemical solution contains the chelating agent (D) to stabilize the peroxide (A1 b) or the peracid (A2) in the chemical solution.
Examples of the chelating agent include hydroxyethylenediphosphonic acid (HEDP), nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), glutamic diacetic acid (CMGA), aminotrimethylenephosphonic Acid (ATMP), ethylenediaminetetramethylenephosphonic acid (EDTMP), phosphonobutanetricarboxylic acid (PBTC), citric acid, succinic acid, oxalic acid, phthalic acid, malic acid, tartaric acid, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), and glycoletherdiaminetetraacetic acid (GEDTA).
These chelating agents can be used as salts such as alkali metal salts and ammonium salts.
The content of the chelating agent (D) in the chemical solution is not particularly limited within a range that does not impair the desired effect. The content of the chelating agent (D) in the chemical solution is preferably in a range of 0.001 to 10 mass%, more preferably 0.01 to 5 mass%, and still more preferably 0.1 to 2 mass%, based on the mass of the chemical solution.
[ Water-soluble organic solvent (O) ])
The chemical solution may contain a water-soluble organic solvent (O) within a range not to impair the desired effect. By containing the chemical solution with the water-soluble organic solvent (O), components that are difficult to dissolve in water (W) can be easily dissolved in the chemical solution.
Specific examples of the water-soluble organic solvent (O) include: sulfolane; hexamethylphosphoric triamide; sulfoxides such as dimethyl sulfoxide; sulfones such as dimethyl sulfone, diethyl sulfone, ethyl methyl sulfone, ethyl isopropyl sulfone, 3-methyl sulfone, bis (2-hydroxyethyl) sulfone and tetramethylene sulfone; amides such as N, N-dimethylformamide, N-methylformamide, N-dimethylacetamide, N-methylacetamide, and N, N-diethylacetamide; lactams such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, and N-hydroxyethyl-2-pyrrolidone; imidazolinones such as 1, 3-dimethyl-2-imidazolidinone, 1, 3-diethyl-2-imidazolidinone, and 1, 3-diisopropyl-2-imidazolidinone; alkanols such as methanol, ethanol, and isopropanol; polyhydric alcohols such as ethylene glycol, propylene glycol, 1, 2-butanediol, 1, 3-butanediol, 2, 3-butanediol, glycerin, diethylene glycol and the like; lactones such as beta-propiolactone, gamma-butyrolactone, delta-valerolactone, gamma-valerolactone and gamma-nonalactone; propylene carbonate; tetrahydrofuran; and nitrogen-containing heterocyclic compounds which are liquid at 25 ℃ under atmospheric pressure and do not belong to the anticorrosive (B) such as the lactams described above, 1-methylimidazole, and 1- (3-aminopropyl) imidazole, piperidine, and 2-oxazolidinone.
The content of the water-soluble organic solvent (O) in the chemical solution is not particularly limited as long as the desired effect is not impaired. For example, the content of the water-soluble organic solvent (O) in the chemical solution is preferably 50% by mass or less, more preferably 30% by mass or less, and still more preferably 10% by mass or less, with respect to the mass of the chemical solution. The chemical solution preferably contains only water (W) as a solvent.
[ other Components ]
The chemical solution may contain an antifoaming agent and the like in addition to the above components. The amounts of these components to be used are appropriately determined in consideration of the amounts usually used for the respective components.
[ Water (W) ])
The water (W) is not particularly limited as long as the desired effects are not impaired, and water of various qualities can be used. The water (W) is preferably ion-exchanged water, distilled water, ion-exchanged distilled water, or the like, and more preferably ion-exchanged distilled water.
The chemical solutions are prepared by dissolving the essential or optional components of the chemical solutions described above in water (W) in desired amounts.
By using the chemical solution described above, it is possible to satisfactorily etch the copper thin film as the seed layer and prevent excessive etching of the copper-plated shaped article.
More specifically, the chemical solution described above preferably has a ratio of the etching rate ER1 to the copper-plated shaped object to the etching rate ER2 to the copper thin film, i.e., ER2/ER1, of 2.5 or more, more preferably 2.9 or more, and particularly preferably 3.0 or more.
The value of the ratio ER2/ER1 tends to be larger as the content of acetic acid or peracetic acid in the chemical solution is larger.
The contact angle of the chemical solution on the surface of the copper-plated shaped article is preferably less than 100 °, more preferably 95 ° or less, still more preferably 90 ° or less, and particularly preferably 85 ° or less. Here, the contact angle is a value measured before the plating shaped object and the chemical solution come into contact with each other.
By making the contact angle of the chemical solution in the surface of the copper-plated shaped object satisfy the above-described conditions, even when the copper thin films are located in the vicinity of the lower portions of the plurality of copper-plated shaped objects adjacent to each other at an extremely close position, the chemical solution can favorably intrude into the gaps between the copper-plated shaped objects, and the copper thin films can favorably be etched.
Examples of the method for lowering the contact angle of the chemical solution include a method of adding the surfactant (C) to the chemical solution and a method of adding a water-soluble organic solvent to the chemical solution.
Here, the contact angle of the chemical solution is a static contact angle. The static contact angle of the chemical solution can be measured, for example, as a contact angle after dropping a droplet of 2.0. Mu.L of the chemical solution on the surface of the copper-plated shaped article after contacting the chemical solution using Dropmaster 700 (manufactured by Kagaku Kogyo Co., ltd.) for 5 seconds.
When the chemical solution and the copper-plated shaped article are brought into contact for 200 seconds, the arithmetic mean height Ra of the surface of the copper-plated shaped article as measured by an Atomic Force Microscope (AFM) is preferably 35nm or less, more preferably 30nm or less, and still more preferably 20nm or less.
When the chemical solution and the copper-plated shaped article are brought into contact for 200 seconds, the root-mean-square height Rq of the surface of the copper-plated shaped article measured by an Atomic Force Microscope (AFM) is preferably 50nm or less, more preferably 40nm or less, and still more preferably 30nm or less.
When the chemical solution and the copper-plated shaped article are brought into contact for 200 seconds, the Z range (Z range) of the surface of the copper-plated shaped article measured by an Atomic Force Microscope (AFM) is preferably 500nm or less, more preferably 400nm or less, and still more preferably 300nm or less. The Z range is a difference between a value of the highest height and a value of the lowest height with respect to height information on irregularities of a measurement target surface before a plane fitting process obtained by an Atomic Force Microscope (AFM).
Method for manufacturing substrate with copper-plated shaped article
The method for manufacturing a substrate with a copper-plated shaped object comprises the following steps:
forming a copper thin film on a substrate;
forming a mold for plating on the copper thin film;
a step of plating copper on a substrate provided with a mold and forming a copper-plated molded article in the mold;
a step of separating the mold after the formation of the copper-plated molded article; and
and a step of etching the copper thin film using the chemical solution after the mold is peeled.
The chemical solution is partially as described above with respect to the step of forming a copper thin film on a substrate, the step of forming a mold for plating on the copper thin film, the step of performing copper plating on the substrate provided with the mold and forming a copper-plated shaped object in the mold, and the step of peeling off the mold after the formation of the copper-plated shaped object.
In the step of etching the copper thin film with the chemical solution after the mold is peeled off, the etching method is not particularly limited as long as the copper thin film can be brought into contact with the chemical solution.
Examples of the method of etching by bringing the chemical solution into contact with the object to be processed in which the substrate, the copper thin film, and the copper-plated shaped article are stacked in this order in the thickness direction of the substrate include a spraying method, a dipping method, and a liquid filling method.
In etching by the spray method, for example, an object to be processed is conveyed or rotated in a predetermined direction, and an etching liquid is sprayed into the space to contact the object to be processed with the etching liquid. The etching solution may be sprayed while rotating the object to be processed by using a spin coater as necessary.
In etching by the immersion method, the object to be processed is immersed in a liquid bath made of a chemical solution, and the object to be processed is brought into contact with the chemical solution in the liquid bath.
In etching by the liquid filling method, a chemical liquid is filled on the surface of an object to be processed to be etched, and the object to be processed is brought into contact with the chemical liquid.
These etching methods may be used flexibly as appropriate depending on the structure, material, and the like of the object to be processed.
The time for bringing the chemical solution into contact with the object to be treated is determined as appropriate in consideration of the thickness of the copper thin film and the like. The temperature of the chemical solution during etching is not particularly limited as long as the copper-plated shaped article is not excessively etched or the substrate is not damaged. The temperature of the chemical solution is typically preferably 10 ℃ to 40 ℃, and more preferably 15 ℃ to 30 ℃.
Examples
The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples.
[ examples 1 to 9 and comparative example 1 ]
In the examples and comparative examples, an object to be processed was used, and the object to be processed was provided with: a silicon substrate having a titanium thin film on one principal surface, a copper thin film having a thickness of 800nm formed by physical vapor deposition coating the exposed surface of the titanium thin film in the silicon substrate, and a copper-plated molded article having a thickness of 4 μm partially coating the copper thin film.
The kinds and amounts of the respective components described in table 1 were uniformly mixed to obtain chemical solutions of examples 1 to 9 and comparative example 1.
In the examples, 1,2, 4-triazole was used as the anticorrosive agent (B). In the examples, the following C1 to C3 were used as the surfactant (C). In the examples and comparative examples, hydroxyethylidene diphosphonic acid (HEDP) was used as the chelating agent (D).
C1: OLFINE EXP4200 (manufactured by Risin chemical industry)
C2: SURFYNOL104 (made by air chemical products)
C3: SURFYNOL465 (made by air chemical products)
Hydrogen peroxide was added to the chemical solution as a hydrogen peroxide solution having a concentration of 31 mass% containing 0.56 parts by mass of hydrogen peroxide and 1.24 parts by mass of water. That is, of the amounts of water (W) described in table 1, 1.24 parts by mass were derived from hydrogen peroxide water.
Using the obtained chemical solution, the etching rate, the contact angle between the surface of the copper thin film and the surface of the copper-plated shaped article, and the surface roughness of the surface of the copper-plated shaped article after contact with the chemical solution were measured by the following methods. The results of these measurements are reported in Table 2.
< measurement of etching Rate >
In the chemical solutions of examples and comparative examples at about 20 ℃, the object to be treated was immersed for 200 seconds, and then the film thickness of the copper thin film and the film thickness of the copper-plated molded article were measured by a sheet resistance meter, and the etching rate was calculated (etching rate: (
Figure BDA0003531751670000151
In seconds).
< measurement of contact Angle with medical solution >
The contact angle of the chemical solution on the surface of the copper thin film and the surface of the copper-plated shaped article was measured by the above-described method using the object before contact with the chemical solution as a sample.
< measurement of surface roughness of surface of copper-plated molded article after contact with chemical solution >
The object was immersed in the chemical solutions of examples and comparative examples at about 20 ℃ for 200 seconds, and then the surface of the object was rinsed with ion-exchanged distilled water for 30 seconds. After the rinsing, the object was dried by blowing nitrogen gas for 20 seconds.
The object after drying was used as a measurement sample, and the arithmetic average height Ra, root mean square height Rq, and Z range of the surface of the copper-plated shaped article were measured using an Atomic Force Microscope (AFM).
[ TABLE 1 ]
Figure BDA0003531751670000161
[ TABLE 2 ]
Figure BDA0003531751670000162
As is clear from tables 1 and 2, when the etching treatment is performed on the object to be treated in which the silicon substrate provided with the titanium thin film, the copper thin film formed by the physical vapor deposition method, and the copper-plated shaped object are sequentially stacked, by the chemical solution of the example containing the oxidizing substance (a) containing the oxoacid (A1 a) and the peroxide (A1 b), and containing water (W), and containing acetic acid as the oxoacid (A1 a), the copper thin film can be etched well, and the excessive etching of the copper-plated shaped object can be prevented.
On the other hand, as is clear from tables 1 and 2, when a chemical solution containing an oxidizing substance (a) containing an oxoacid (A1 a) and a peroxide (A1 b), and containing water (W) but not acetic acid is used, the copper-plated shaped article is etched in a large amount.

Claims (9)

1. A chemical solution used for etching an object to be processed in which a substrate, a copper thin film and a copper-plated molded article are stacked in this order in the thickness direction of the substrate,
the chemical liquid contains an oxidizing substance (A) and water (W),
the oxidizing substance (A) comprises a combination of an oxo acid (A1 a) and a peroxide (A1 b) or comprises a peracid (A2),
the oxidizing substance (A) contains at least one of acetic acid as the oxoacid (A1 a) and peracetic acid as the peracid (A2),
the copper thin film covers at least a part of the main surface of the substrate,
the copper thin film is a film formed by a method other than plating,
the copper-plated shaped article is formed by plating using the copper thin film as a seed layer.
2. The medical solution according to claim 1, further comprising an anticorrosive agent (B).
3. The medical solution according to claim 1 or 2, further comprising a surfactant (C).
4. The medical solution according to claim 1 or 2, wherein the oxo acid (A1 a) comprises phosphoric acid or the peracid (A2) comprises perphosphoric acid.
5. The chemical according to claim 1 or 2, wherein a ratio ER2/ER1 of an etching rate ER1 of the copper-plated shaped article to an etching rate ER2 of the copper thin film is 2.5 or more.
6. The chemical according to claim 1 or 2, wherein a contact angle of the chemical on a surface of the copper-plated shaped article in a state of not being in contact with the chemical is less than 100 °.
7. The chemical solution according to claim 1 or 2, which is prepared from A1 st solution containing the acetic acid as the oxoacid (A1 a) and water (W), and
a2 nd liquid containing the peroxide (A1 b).
8. A method for manufacturing a substrate having a copper-plated shaped object, comprising:
forming a copper thin film on a substrate;
forming a mold for plating on the copper thin film;
a step of plating copper on the substrate provided with the mold and forming a copper-plated molded article in the mold;
a step of peeling off the mold after the formation of the copper-plated molded article;
and a step of etching the copper thin film using the chemical solution according to claims 1 to 7 after the mold is peeled.
9. The method of manufacturing a substrate with a copper-plated shaped article according to claim 8, wherein the copper thin film is formed on the substrate by a physical vapor deposition method.
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