JP2006265632A - Electrolytic copper plating bath and copper plating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acidic electrolytic copper plating bath which has an excellent uniformity of electrodeposition and also exhibits high via filling ability. <P>SOLUTION: The acidic electrolytic copper plating bath contains a soluble copper saltand base acid. The base acid is an organic acid, and a specific aliphatic thiaminocarboxylic acid or its salt (e.g. methionine), aliphatic mercaptocarboxylic acic or its salts (e.g. mercaptosuccinic acid), sulfides (e.g. 3, 6-dithiaoctane-1, 8-diol), aminocarboxylic acids (e.g. diethylene triamine pentaacetic acid) or thioureas are selected for a complexing agent. The plating bath including the complexing agent of the kinds complying with the complexing agent is also effective regardless of the kinds of the base acid. Since the copper bath of the organic acid or the inorganic acid includes the specific complexing agent, the copper bath is higher in uniform electrodeposition characteristics to a base surface than the conventional sulfuric acid copper bath. Further, the bath had the high via hilling ability. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrolytic copper plating bath and a copper plating method, by adding each specific complexing agent to a bath regardless of the type of acid, or an organic acid bath, and is excellent in uniform electrodeposition on the substrate surface, In particular, when electrolytic copper plating is applied to a substrate in which a via hole and a through hole are mixed, a copper filling (via filling) to the via hole and uniform electrodeposition to the through hole can be achieved satisfactorily.

Conventionally known copper electroplating baths include a copper sulfate bath based on sulfuric acid, a copper pyrophosphate bath, a copper cyanide bath, and the like. Among these, the copper cyanide bath has good throwing power, but the leveling ability is insufficient and the waste water treatment is also required.
In addition, the copper sulfate bath and pyrophosphate bath have a leveling effect larger than that of the copper cyanide bath, but still have insufficient points in terms of throwing power. In addition, when applied to a substrate having a mixture of via holes and through holes, the via filling needs to be thick at the bottom of the via and thin around the via, which is mechanically different from the uniform electrodeposition. (Or contradictory), it is not easy to achieve both via filling and uniform electrodeposition on the through hole.

Conventionally, electrolytic copper plating baths containing various complexing agents are known.
First, there are following Patent Documents 1 to 3 as copper plating baths containing aminocarboxylic acids such as ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA).
(1) Patent Document 1
For the purpose of forming a copper plating film with good adhesion on a non-conductive material, for electroless plating alternatives containing complexing agents such as EDTA, DTPA, nitrile triacetic acid (NTA) and iminodiacetic acid (IDA) A copper strike plating method is disclosed (see claim 3, paragraphs 9 and 17).
(2) Patent Document 2
For the purpose of forming a copper plating film having excellent adhesion on the surface of the rare earth permanent magnet, 0.05 to 0.7 mol / L of EDTA and 0.1 to 1.0 of tartrate or citrate are used. An alkaline copper plating solution (pH 11.0 to 13.0) containing mol / L is disclosed (see claim 1).
(3) Patent Document 3
A copper plating solution containing a complexing agent such as EDTA, IDA or ethylenediamine has been disclosed for the purpose of reliably copper-filling in a fine recess (see claims 1 and 2).
(4) Patent Document 4
For the purpose of facilitating handling with low viscosity, a method for producing a copper oxide slurry in which a complexing agent such as EDTA, tartaric acid or NTA is added as a dispersant is disclosed (see claims 1 to 3).

Next, there are the following Patent Documents 5 to 8 for copper plating baths containing cysteine, aliphatic sulfides, or aliphatic mercaptans.
(5) Patent Document 5
In making a copper wire having a very thin diameter, it is disclosed that a copper foil is deposited by an electrolyte solution containing an organic additive such as cysteine, sulfopropyl disulfide, or tetraethylthiuram disulfide (see claims 12 to 16). ).
(6) Patent Document 6
3-mercapto-1-propanesulfonic acid, bis (2-mercaptoethyl) sulfide (HS—CH ₂ CH ₂ —S—CH ₂ CH ₂ —SH), thiodiethanol (ie, thiodiglycol; HO—CH ₂ CH An acidic electrolytic copper plating bath containing a water-soluble mercapto group-containing organic brightener such as _2- S—CH ₂ CH ₂ —OH) is disclosed (see claims 1 to 3 and paragraph 15). Further, it is disclosed that 1,3-bis (3-pyridylmethyl) -2-thiourea, N, N′-ethylenethiourea and the like can be added as a leveling agent (see claim 6, paragraph 18). ).
(7) Patent Document 7
A copper plating bath containing an organic additive composed of disulfides has been disclosed for the purpose of preventing a decrease in filling properties and generation of voids (see claims 6 to 8). However, there are no specific examples of disulfides (see paragraphs 11 and 22).
(8) Patent Document 8
A copper plating bath containing a brightener comprising a sulfide compound and a sulfonic acid group-containing compound is disclosed (see claims 6 to 8). Examples of the brightener include 3-mercapto-propylsulfonic acid (sodium salt) and the like (see paragraph 27).

Next, there are Patent Documents 9 to 11 as copper plating baths containing thioureas.
(9) Patent Document 9
It is disclosed that a copper film is formed using a copper plating bath containing a thiourea-based additive or the like when producing a copper-coated aluminum wire for the purpose of improving solderability. 3).
Patent Document 6 discloses that a copper plating bath contains 2,5-dithiourea, 1-phenyl-2-thiourea, ethylenethiourea or the like as a leveling agent (Claim 6). (See paragraph 18).
(10) Patent Document 10
It is disclosed that via holes are filled and formed with a copper plating bath containing thioureas for the purpose of filling and forming via holes in a multilayer printed wiring board (see claim 1).
(11) Patent Document 11
Although not a copper plating bath, a copper stripping agent containing thioureas and an acid selected from sulfuric acid, hydrochloric acid, carboxylic acid and the like is disclosed (see claims 1 and 2).

JP-A-5-44075 JP 2004-137533 A JP 2002-80992 A Japanese Patent Laid-Open No. 11-158644 Japanese National Patent Publication No. 10-510883 JP 2001-73182 A JP 2004-143478 A JP 2001-3191 A JP 2001-271198 A JP 2000-188476 A Japanese Patent Laid-Open No. 11-158659

In the copper plating bath containing the above complexing agent, the throwing power is not much different from general copper sulfate baths, and it is difficult to expect improvement in throwing power to the through hole (see the test example below). ).
Further, when applied to a substrate in which via holes and through holes are mixed, as described above, via filling and uniform electrodeposition are mechanically different, and there are many problems to achieve these simultaneously.
This invention makes it a technical subject to be able to cope with a via filling well while being excellent in the uniform electrodeposition property in an acidic electrolytic copper plating bath.

From the standpoint of superior electrodeposition properties compared to conventional copper sulfate baths, the present applicant has previously identified specific oxycarboxylic acids (such as glycolic acid) or salts thereof, or these oxycarboxylic acids and organic compounds. A copper plating bath using a mixed acid of sulfonic acid as a base acid has been proposed (see Japanese Patent Application No. 2005-11570).
In the case where electroplating is performed using a copper bath containing various complexing agents with reference to this prior application and the EDTA and thioureas described in Patent Documents 1 to 10 above, As a result of diligent research on the uniform electrodeposition on the substrate surface and the degree of via filling, when a specific aliphatic thioaminocarboxylic acid, aliphatic mercaptocarboxylic acid or sulfide is selected as a complexing agent, It is excellent in electrodeposition, and can also achieve via filling well, and when these specific complexing agents are contained, it exhibits effectiveness regardless of the type of base acid, We found that the effectiveness of organic acid baths can be ensured with a wide range of complexing agents compared to inorganic acid baths such as sulfuric acid, and in particular, copper glycolic acid baths using methionine as a complexing agent can be expected to have better effects. Thus, the present invention has been completed.

That is, the present invention 1 is an electrolytic copper plating bath containing a soluble copper salt, a base acid and a complexing agent.
The complexing agent is at least one of the following compounds (A) to (E)
(A) an aliphatic thioaminocarboxylic acid or a salt thereof selected from the group consisting of methionine, ethionine, cystine, and N-acetylcysteine
(B) an aliphatic mercaptocarboxylic acid selected from the group consisting of mercaptoisobutyric acid, mercaptoacetic acid, dimercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, mercaptosuccinic acid, and 2,3-dimercaptosuccinic acid, or Its salt
(C) Sulfides represented by the following general formula (1) Ra- (A) j-S- (B) k-Rb (1)
(In the formula (1), j and k are integers of 1 to 100; A and B may be the same or different, and methylene, ethylene, 1,3-propylene, 1,2-propylene, 1,4, respectively. -Butylene, 1,2-butylene, 1,3-butylene, or these C ₂ -C ₄ oxyalkylenes; Ra and R b may be the same or different and each is H (where A and B are both methylene) In the case of C ₂ -C ₄ alkylene, either Ra or R b is not H. Also, when both A and B are C ₂ -C ₄ oxyalkylene, when j and k are both 1, Ra And Rb are not H.), OH, NH ₂ , CO ₂ M, SO ₃ M, pyridyl group or aminophenyl group; M is an alkali metal, alkaline earth metal, ammonium or amine)
(D) the following general formula sulfides represented by (2) Ra-S- (CH 2 CH 2 -S) n-Rb ... (2)
(In the formula (2), n is an integer of 1 to 3; Ra and Rb may be the same or different, and are each — (CH ₂ ) m —R c; m is an integer of 0 or 1 to 5; There; Rc is a pyridyl group or an aminophenyl group when m is 0, when m is an integer from 1 to 5 be _{OH, NH 2, CO 2 M} , SO 3 M, pyridyl or aminophenyl group M is an alkali metal, alkaline earth metal, ammonium or amine)
(E) A thiourea derivative represented by the following general formula (3) Rd—NH—C (═S) —NH—Re (3)
(In the formula (3), Rd and Re may be the same or different and each is — (CH ₂ ) p—Rf; p is an integer of 2 to 5; Rf is a pyridyl group)
An electrolytic copper plating bath characterized by

Invention 2 is an electrolytic copper plating bath containing a soluble copper salt, a base acid and a complexing agent.
The base acid is an organic acid or a salt thereof, and the complexing agent is at least one of the following compounds (a) to (f) (provided that the base acid is tartaric acid, citric acid or a salt thereof, Is a compound (a) to (e) or a compound (f) excluding ethylenediaminetetraacetic acid)
(a) an aliphatic thioaminocarboxylic acid or a salt thereof selected from the group consisting of methionine, ethionine, cystine, N-acetylcysteine and cysteine
(b) an aliphatic mercaptocarboxylic acid selected from the group consisting of mercaptoisobutyric acid, mercaptoacetic acid, dimercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, mercaptosuccinic acid, and 2,3-dimercaptosuccinic acid, or Its salt
(c) Sulfides represented by the following general formula (1) Ra- (A) j-S- (B) k-Rb (1)
(In the formula (1), j and k are integers of 1 to 100; A and B may be the same or different, and methylene, ethylene, 1,3-propylene, 1,2-propylene, 1,4, respectively. -Butylene, 1,2-butylene, 1,3-butylene, or these C ₂ -C ₄ oxyalkylenes; Ra and R b may be the same or different and each is H (where A and B are both methylene) In the case of C ₂ -C ₄ alkylene, one of Ra and R _b is not H), OH, NH ₂ , CO ₂ M, SO ₃ M, a pyridyl group or an aminophenyl group; M is an alkali metal, (Alkaline earth metal, ammonium, amine)
(d) the following general formula sulfides represented by (2) Ra-S- (CH 2 CH 2 -S) n-Rb ... (2)
(In the formula (2), n is an integer of 1 to 3; Ra and Rb may be the same or different, and are each — (CH ₂ ) m —R c; m is an integer of 0 or 1 to 5; There; Rc is a pyridyl group or an aminophenyl group when m is 0, when m is an integer from 1 to 5 be _{OH, NH 2, CO 2 M} , SO 3 M, pyridyl or aminophenyl group M is an alkali metal, alkaline earth metal, ammonium or amine)
(e) At least one of thiourea and thiourea derivatives
(f) Hydroxyethylethylenediaminetriacetic acid, N, N-dicarboxymethyl-L-glutamic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, glutamic acid, N, N-dicarboxymethyl-L-aspartic acid, diethylenetriaminepentaacetic acid, triethylenetetramine Hexaacetic acid, iminodiacetic acid, iminodipropionic acid, aspartic acid, hydroxyethylidene diphosphonic acid, nitrilotris (methylenephosphonic acid), phosphonobutanetricarboxylic acid, hydroxyethylaminodimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, N, N-dicarboxymethyl-L-alanine, 1,3-propanediaminetetraacetic acid, glycol ether diaminetetraacetic acid, ethylenediamine disuccinic acid, alanine, hydroxy An aminocarboxylic acid selected from the group consisting of ethyliminodiacetic acid, glycine, 1,3-diamino-2-hydroxypropanetetraacetic acid, ornithine, N, N-bis (2-hydroxyethyl) glycine, aminophosphonic acid, phosphonic acid, An electrolytic copper plating bath characterized by being at least one of phosphonocarboxylic acid or a salt thereof.

  Invention 3 is an electrolytic copper plating bath according to Invention 1 or 2, wherein the complexing agent is methionine.

  Invention 4 is an electrolytic copper plating bath according to Invention 2 or 3, wherein the organic acid is oxycarboxylic acid or organic sulfonic acid.

  The present invention 5 is the electrolytic copper plating bath according to the present invention 4, wherein the oxycarboxylic acid is glycolic acid.

  The present invention 6 is the electrolytic copper plating bath according to the present invention 4, wherein the organic sulfonic acid is methanesulfonic acid or 2-hydroxyethanesulfonic acid.

  The present invention 7 is an electrolytic copper plating bath according to the present invention 2, wherein the complexing agent is methionine and the organic acid is glycolic acid.

  Invention 8 is an electrolytic copper plating bath according to any one of Inventions 1 to 7, further comprising an additive such as a leveler or brightener.

  The present invention 9 is an electrolytic copper plating method characterized in that a copper plating film is formed on an object to be plated in which via holes and through holes are mixed using the electrolytic copper plating bath according to any one of the present inventions 1 to 8. .

Because it is a copper plating bath containing a complexing agent selected from specific aliphatic thioaminocarboxylic acids, aliphatic mercaptocarboxylic acids, or sulfides, the surface of the substrate is higher than conventional copper sulfate baths. It is excellent in throwing power to the surface, and particularly shows high ability in throwing power through holes. In copper plating baths containing these specific complexing agents, the base electrode can improve the throwing power regardless of whether it is an inorganic acid or an organic acid, but it is better to select an organic acid as the base acid. Effectiveness can be ensured with a wider range of complexing agents.
In addition, the copper plating bath of the present invention can sufficiently cope with not only the above-described uniform electrodeposition, but also via filling, and even when applied to a substrate in which via holes and through holes are mixed, copper filling into the via holes and uniform to the through holes are possible. Both electrodeposition properties can be achieved well.

The present invention is firstly an electrolytic copper plating bath containing a complexing agent such as specific aliphatic thioaminocarboxylic acids, aliphatic mercaptocarboxylic acids, or sulfides (corresponding to the present invention 1). Secondly, an electrolytic copper plating bath containing a specific complexing agent (a broader range of complexing agents than the first invention) and using an organic acid such as oxycarboxylic acid or organic sulfonic acid as a base acid (this book) (Equivalent to Invention 2) Third, there is an electrolytic copper plating method in which a copper plating film is formed on an object to be plated in which via holes and through holes are mixed using these copper plating baths.
The electrolytic copper plating bath of the present invention is basically an acidic copper plating bath, and the bath management is easier than the conventional alkaline copper bath.

The electrolytic copper plating bath of the present invention 1 has a basic composition of a soluble copper salt and a specific complexing agent. Therefore, it can be applied to any inorganic acid bath and organic acid bath including a bath based on sulfuric acid and pyrophosphoric acid known in the prior art (that is, the base acid of the electrolytic copper plating bath is an inorganic acid, an organic acid or a salt thereof). Regardless of whether there are any special restrictions).
Any soluble copper salt may be used as long as it is a soluble salt that generates cuprous or cupric ions in an aqueous solution, and there is no particular limitation, and hardly soluble salts are not excluded. Specific examples include copper sulfate, copper oxide, copper chloride, copper carbonate, copper acetate, copper pyrophosphate, copper oxalate, and the like, with copper sulfate and copper oxide being preferred.
The metal equivalent content of the soluble copper salt is 0.015 to 3.2 mol / L, preferably 0.1 to 1.2 mol / L.
Examples of the inorganic acid as the base acid include sulfuric acid, pyrophosphoric acid, and borofluoric acid. Examples of the organic acid include oxycarboxylic acids such as glycolic acid and tartaric acid, and organic sulfonic acids such as methanesulfonic acid and 2-hydroxyethanesulfonic acid, as in the case of the present invention 2 described later.
The content of the base acid with respect to the plating bath is preferably 0.1 to 12 mol / L, and more preferably 0.2 to 3.0 mol / L.

The electrolytic copper plating bath of the present invention 1 uses a sulfur-containing compound selected from a specific thioaminocarboxylic acid or a salt thereof, an aliphatic mercaptocarboxylic acid or a salt thereof, sulfides, or a thiourea derivative as a complexing agent. There are features.
These sulfur-containing compounds can be used singly or in combination, or different types can be used together (for example, thioaminocarboxylic acid and sulfides can be used together). The addition amount of the sulfur-containing compound is preferably 0.5 to 10 times mol, more preferably 1.0 to 5.0 times mol for the copper ion in the bath. If the concentration is lower than the appropriate concentration range, the throwing power is reduced (particularly, the throwing power and via filling may not be compatible). Is useless.

The aliphatic thioaminocarboxylic acid can be selected from the group consisting of methionine, ethionine, cystine and N-acetylcysteine, preferably methionine, cystine and N-acetylcysteine, more preferably methionine.
The aliphatic mercaptocarboxylic acid can be selected from the group consisting of mercaptoisobutyric acid, mercaptoacetic acid, dimercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, mercaptosuccinic acid, and 2,3-dimercaptosuccinic acid. Acetic acid, dimercaptoacetic acid and mercaptosuccinic acid are preferred, and mercaptosuccinic acid is more preferred.

The sulfides are specific compounds represented by general formula (1) or general formula (2).
The sulfides represented by the general formula (1) include thiodiglycolic acid, 2,2'-thiobis (ethylamine), thiodipropionic acid, thiodiethanesulfonic acid, thiodipropanol, and 3,3'-thiobis. (Propylamine), thiodibutyric acid, thiodipropanesulfonic acid, bis (undecaethylene glycol) thioether, bis (dodecaethylene glycol) thioether, bis (pentadecaethylene glycol) thioether, bis (triethylene glycol) thioether, etc. It is done. Preferred examples include thiodiglycolic acid, 2,2'-thiobis (ethylamine), thiodipropionic acid, thiodiethanesulfonic acid, thiodipropanol, 3,3'-thiobis (propylamine), thiodibutyric acid, thiodiglycol Propanesulfonic acid, bis (undecaethylene glycol) thioether, bis (pentadecaethylene glycol) thioether, bis (triethylene glycol) thioether, thiodiglycolic acid, bis (undecaethylene glycol) thioether, bis (pentadeca More preferred are ethylene glycol) thioether and bis (triethylene glycol) thioether.

In the general formula (1) of the above sulfides, when both A and B are C ₂ -C ₄ oxyalkylene, when j = k = 1, Ra and Rb are not H. In thiodiethanol (= thiodiglycol; H— (OCH ₂ CH ₂ ) —S— (CH ₂ CH ₂ O) —H) described in paragraph 15), A = B = oxyethylene, j In view of the fact that = k = 1 and Ra = Rb = H, thiodiglycol is excluded from the sulfides of the present invention.
When both A and B are methylene or C ₂ -C ₄ alkylene, either Ra or R b is not H. For example, diethyl sulfide (H— (CH ₂ CH ₂ ) —S— (CH ₂ CH ₂ ) -H) is excluded from the sulfides of the present invention in view of A = B = ethylene and Ra = Rb = H.
Therefore, a specific example of the aforementioned sulfides will be described according to the general formula (1). A and B are methylene, j and k which are addition numbers thereof are both 1, and Ra and Rb are COOH. In the case it represents HOOC—CH ₂ —S—CH ₂ —COOH, meaning thiodiglycolic acid. When A and B are ethylene, j and k which are addition numbers thereof are both 1, and Ra and Rb are NH ₂ , H ₂ N—CH ₂ CH ₂ —S—CH ₂ CH ₂ —NH ₂ represents 2,2'-thiobis (ethylamine). When A and B are oxyethylene, j and k which are addition numbers thereof are both 11, and Ra and Rb are H, H— (OCH ₂ CH ₂ ) ₁₁ —S— (CH ₂ CH ₂ O) ₁₁ -H, which means bis (undecaethylene glycol) thioether. When A and B are oxyethylene, the addition numbers j and k are both 15, and Ra and Rb are H, H— (OCH ₂ CH ₂ ) ₁₅ —S— (CH ₂ CH ₂ O ) ₁₅ -H, which means bis (pentadecaethylene glycol) thioether.

Examples of the sulfides represented by the general formula (2) include 4,7,10-trithiatridecane-1,2,12,13-tetraol, 6,9,12-trithia-3,15-dioxahepta. Decane-1,17-diol, 3,6-dithiaoctane-1,8-diol, 4,7-dithiadecane-1,10-diol, 3,6,9-trithiaundecane-1,11-diol, 3, 6-dithiaoctane-1,8-diamine, 3,6-dithiaoctane-1,8-dicarboxylic acid, 4,7,10-trithiatridecane-1,13-disulfonic acid disodium salt, 3,6,9-trithia Examples include undecane-1,11-disulfonic acid, 4,7,10,13-tetrathiahexadecane-1,16-disulfonic acid, 1,8-bis (2-pyridyl) -3,6-dithiaoctane. Preferred examples are 3,6-dithiaoctane-1,8-diol, 4,7-dithiadecane-1,10-diol, 1,8-bis (2-pyridyl) -3,6-dithiaoctane, 4,7,10. -Trithiatridecane-1,13-disulfonic acid disodium salt, 3,6,9-trithiaundecane-1,11-disulfonic acid, 3,6-dithiaoctane-1,8-diol, 4,7-dithiadecane -1,10-diol is more preferred.
For example, in the general formula (2), an additional number n is 1, Ra and Rb are both - in the case of (CH ₂₎ (a m = 2, Rc = OH) 2 -OH is, HO-CH ₂ It represents _{CH 2 -S-CH 2 CH 2} -S-CH 2 CH 2 -OH, means 3,6-dithiaoctane-1,8-diol. When the addition number n is 1 and Ra and Rb are both — (CH ₂ ) ₃ —OH (m = 3, R c = OH), HO—CH ₂ CH ₂ CH ₂ —S—CH ₂ It represents _{CH 2 -S-CH 2 CH 2} CH 2 -OH, means 4,7 Jichiadekan 1,10-diol. When the addition number n is 2 and Ra and Rb are both — (CH ₂ ) ₃ —SO ₃ Na (m = 3, R c = SO ₃ M (M = Na)), NaO ₃ S— CH ₂ CH ₂ CH ₂ —S— (CH ₂ CH ₂ S) ₂ —CH ₂ CH ₂ CH ₂ —SO ₃ Na represents 4,7,10-trithiatridecane-1,13-disulfonic acid disodium salt means.

The thiourea derivative is a thiourea compound having a pyridine ring represented by the general formula (3). Examples of the thiourea derivative include 1,3-bis (3-pyridylethyl) -2-thiourea, 1,3-bis (4-pyridylpentyl) -2-thiourea, and the like. (3-pyridylmethyl) -2-thiourea and 1,3-bis (3-pyridylethyl) -2-thiourea are preferred.
In the general formula (3) of the thiourea derivative, since the number p of methylene bonded to the nitrogen atom is 2 to 5, for example, 1,3-bis (described in Patent Document 6 (see paragraph 18)) In view of the fact that 3-pyridylmethyl) -2-thiourea is a compound corresponding to p = 1, it is excluded from the thiourea derivative of the present invention.
Therefore, a specific example of the above thiourea derivative will be described in accordance with the general formula (3). For example, in the general formula (3), Rd and Re are both-(CH ₂ ) -Py (p = 2, Py = in the case of the pyridine ring and is) represents a _{Py-CH 2 CH 2 -NH-} C (= S) -NH-CH 2 CH 2 -Py, 1,3- bis (3-pyridylethyl) -2 Means thiourea;

In the electrolytic copper plating bath of the present invention 1, as described above, the base acid can be applied regardless of an inorganic acid, an organic acid or a salt thereof.
On the other hand, the electrolytic copper plating bath of the present invention 2 is based on the above-mentioned prior application of the applicant of the present invention, and in contrast to the present invention 1, a specific complexing agent (a complexing agent in a wider range than the present invention 1). And the base acid is not an inorganic acid, but an organic copper plating bath in which an organic acid such as oxycarboxylic acid or organic sulfonic acid or a salt thereof is limited.
The complexing agent to be contained in the copper plating bath of the present invention 2 is at least one of the compounds (a) to (f).
These compounds can be used singly or in combination, or different kinds (for example, sulfides and aminocarboxylic acids) can be used in combination. The amount of complexing agent added to the plating bath is basically the same as that of the first invention.
The complexing agent (a) of the present invention 2 is obtained by adding cysteine to the complexing agent (A) of the present invention 1. Preferable examples of the complexing agent (a) are methionine, cystine and N-acetylcysteine, and methionine is more preferable.
The complexing agent (b) of the present invention 2 is the same as the complexing agent (B) of the present invention 1. Preferred examples of the complexing agent (b) are mercaptoacetic acid, dimercaptoacetic acid, and mercaptosuccinic acid, with mercaptosuccinic acid being more preferred.
The complexing agent (c) of the present invention 2 is broader than the complexing agent (C) based on the complexing agent (C) of the present invention 1. This point will be explained in accordance with the general formula (1) of the present invention 2. When both A and B are C _{2 to} C ₄ oxyalkylenes, even if j = k = 1, Ra = Rb = H. Not excluded. Therefore, the complexing agent (c) of the present invention 2 includes thiodiglycol (HO—CH ₂ CH ₂ —S—CH ₂ CH ₂ —H). That is, the complexing agent (c) of the present invention 2 is obtained by adding thiodiglycol and the like to the specific example of the complexing agent (C) of the present invention 1. Preferred examples are thiodiglycol and thiodiglycol. Acid, 2,2'-thiobis (ethylamine), thiodipropionic acid, thiodiethanesulfonic acid, thiodipropanol, 3,3'-thiobis (propylamine), thiodibutyric acid, thiodipropanesulfonic acid, bis (un Decaethylene glycol) thioether, bis (pentadecaethylene glycol) thioether, bis (triethylene glycol) thioether, more preferred examples are thiodiglycol, thiodiglycolic acid, bis (undecaethylene glycol) thioether, bis ( Pentadecaethylene glycol) thioether and bis (triethylene glycol) thioether.
The complexing agent (d) of the present invention 2 is the same as the complexing agent (D) of the present invention 1, and preferred examples include 3,6-dithiaoctane-1,8-diol and 4,7-dithiadecane-1. , 10-diol, 1,8-bis (2-pyridyl) -3,6-dithiaoctane, 4,7,10-trithiatridecane-1,13-disulfonic acid disodium, 3,6,9-trithiaundecane 1,11-disulfonic acid, and a more preferred example is 3,6-dithiaoctane-1,8-diol, 4,7-dithiadecane-1,10-diol.
The complexing agent (e) of the present invention 2 is a thiourea or thiourea derivative, and is not limited to a thiourea derivative having a pyridyl group such as the complexing agent (E) of the present invention 1. Examples of the thiourea derivatives include N, N′-dimethylthiourea, trimethylthiourea, diethylthiourea (eg, N, N′-diethylthiourea), N, N′-diisopropylthiourea, allylthiourea, acetylthiourea, ethylenethiourea. N, N'-diphenylthiourea, thiourea dioxide, thiosemicarbazide, S-methylisothiourea sulfate, tributylthiourea, benzylisothiourea hydrochloride, N, N'-dibutylthiourea, 1-naphthylthiourea, tetramethylthiourea 1-phenylthiourea, 1-methylthiourea and the like. A preferred example of the complexing agent (e) of the present invention 2 is thiourea. The thiourea derivative of the present invention 2 includes a thiourea derivative having a pyridyl group. In this case, for example, in the general formula (3) of the present invention 1, the number p of methylene groups is not limited to 2-5, = 1, and 1,3-bis (3-pyridylmethyl) -2-thiourea and the like are included in the thiourea derivative of the present invention 2.
The complexing agent (f) of the present invention 2 is a specific aminocarboxylic acid, aminophosphonic acid, phosphonic acid, phosphonocarboxylic acid or a salt thereof, which is a compound not selected in the present invention 1. These specific aminocarboxylic acids or salts thereof can be used alone or in combination, and different types (for example, aminocarboxylic acid and aminophosphonic acid) may be used in combination.
Examples of the aminocarboxylic acid include hydroxyethylethylenediaminetriacetic acid, N, N-dicarboxymethyl-L-glutamic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, glutamic acid, N, N-dicarboxymethyl-L-aspartic acid, diethylenetriaminepentaacetic acid , Triethylenetetraminehexaacetic acid, aspartic acid, N, N-dicarboxymethyl-L-alanine, 1,3-propanediaminetetraacetic acid, glycol etherdiaminetetraacetic acid, ethylenediamine disuccinic acid, alanine, hydroxyethyliminodiacetic acid, Examples include glycine, 1,3-diamino-2-hydroxypropanetetraacetic acid, ornithine, and N, N-bis (2-hydroxyethyl) glycine.
Examples of the aminophosphonic acid include hydroxyethylaminodimethylenephosphonic acid and diethylenetriaminepentamethylenephosphonic acid.
Examples of the phosphonic acid include hydroxyethylidene diphosphonic acid and nitrilotris (methylenephosphonic acid).
Similarly, the phosphonocarboxylic acid includes phosphonobutanetricarboxylic acid. These specific aminocarboxylic acid salts, aminophosphonic acid salts, phosphonic acid salts, or phosphonocarboxylic acid salts are also included in the complexing agent (f). The salt such as aminocarboxylic acid refers to a sodium salt, potassium salt, calcium salt, magnesium salt, ammonium salt or amine salt.
As the complexing agent (f) of the present invention 2, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, triethylenetetraminehexaacetic acid, iminodiacetic acid, iminodipropionic acid, glutamic acid, and aspartic acid are preferable. More preferred are ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, triethylenetetraminehexaacetic acid and iminodiacetic acid.

The present invention 2 is characterized in that a specific complexing agent is contained in an organic acid bath. The organic acid is not particularly limited, and specifically includes oxycarboxylic acid, organic sulfonic acid, carboxylic acid and the like, and oxycarboxylic acid and organic sulfonic acid are preferable (see the present invention 4).
Examples of the oxycarboxylic acid include glycolic acid, lactic acid, citric acid, malic acid, gluconic acid, and glucoheptonic acid. Glycolic acid, citric acid, gluconic acid, lactic acid, and malic acid are preferable, and glycolic acid is more preferable.
Examples of the organic sulfonic acid include alkane sulfonic acid and alkanol sulfonic acid, which are excellent in waste water treatment and copper salt solubility.
Examples of the alkane sulfonic acid, chemical formula _{C n H 2n + 1 SO 3} H ( e.g., n = 1 to 5) can be used those represented by, in particular, methanesulfonic acid, ethanesulfonic acid, 1-propane In addition to sulfonic acid, 2-propanesulfonic acid, 1-butanesulfonic acid, 2-butanesulfonic acid, pentanesulfonic acid and the like, hexanesulfonic acid, decanesulfonic acid, dodecanesulfonic acid and the like can be mentioned. Preferable examples are methanesulfonic acid, ethanesulfonic acid, 1-propanesulfonic acid, and 2-propanesulfonic acid, and methanesulfonic acid (hereinafter referred to as MSA) is more preferable.

As the alkanol sulfonic acid, those represented by the chemical formula C _m H _{2m + 1} —CH (OH) —C _p H _2p —SO ₃ H (for example, m = 0 to 6, p = 1 to 5) can be used. Specifically, in addition to 2-hydroxyethane-1-sulfonic acid, 2-hydroxypropane-1-sulfonic acid, 2-hydroxybutane-1-sulfonic acid, 2-hydroxypentane-1-sulfonic acid, etc. -Hydroxypropane-2-sulfonic acid, 3-hydroxypropane-1-sulfonic acid, 4-hydroxybutane-1-sulfonic acid, 2-hydroxyhexane-1-sulfonic acid, 2-hydroxydecane-1-sulfonic acid, 2 -Hydroxydodecane-1-sulfonic acid and the like. A preferred example is 2-hydroxyethane-1-sulfonic acid (isethionic acid).
Examples of the organic sulfonic acid include alkane sulfonic acid and alkanol sulfonic acid, but aromatic sulfonic acid is also effective.
Examples of the aromatic sulfonic acid include benzene sulfonic acid, alkylbenzene sulfonic acid, phenol sulfonic acid, naphthalene sulfonic acid, alkyl naphthalene sulfonic acid, and the like. Specifically, 1-naphthalene sulfonic acid, 2-naphthalene sulfonic acid, Examples include toluenesulfonic acid, xylenesulfonic acid, p-phenolsulfonic acid, cresolsulfonic acid, sulfosalicylic acid, nitrobenzenesulfonic acid, sulfobenzoic acid, diphenylamine-4-sulfonic acid, and the like.

As the organic acid, each of oxycarboxylic acid and organic sulfonic acid may be used alone or in combination, or a plurality of kinds may be used in combination. For example, a mixed acid of glycolic acid and methanesulfonic acid or a mixed acid of glycolic acid and isethionic acid may be used as the base acid.
As above-mentioned, 0.1-12 mol / L is preferable and, as for content with respect to the plating bath of an organic acid or its salt, 0.2-3.0 mol / L is more preferable.
The salt of an organic acid refers to a sodium salt, potassium salt, calcium salt, magnesium salt, ammonium salt or amine salt of oxycarboxylic acid.
The copper plating bath of the present invention 2 is an organic acid bath containing a specific complexing agent. As shown in the present invention 7, a glycolic acid bath containing methionine as a complexing agent is preferable. In the organic acid bath of the present invention 2, it is not excluded that a small amount of inorganic acid such as sulfuric acid or pyrophosphoric acid is mixed.

As shown in the present invention 8, the electrolytic copper plating bath of the present invention can of course contain various additives such as levelers, brighteners and chlorides in addition to the above basic composition. Levelers and brighteners have a glossy and smoothing effect on the copper film. Chloride has a function of promoting the glossy and smoothing action of levelers and brighteners.
The leveler is a nitrogen-based organic compound mainly composed of a surfactant or a dye.
As this surfactant, a nonionic surfactant, an amphoteric surfactant, a cationic surfactant, or an anionic surfactant can be used alone or in combination.
Specific examples of the nonionic surfactant include polyethylene glycol (hereinafter referred to as PEG), polypropylene glycol, C ₁ -C ₂₀ alkanol, phenol, naphthol, bisphenols, (poly) C ₁ -C ₂₅ alkylphenol, (poly) aryl phenol, C ₁ -C ₂₅ alkyl naphthol, C ₁ -C ₂₅ alkoxylated phosphoric acid (salt), sorbitan esters, polyalkylene glycol, C ₁ -C ₂₂ aliphatic amines, C ₁ -C ₂₂ aliphatic such as ethylene oxide (EO) and / or propylene oxide (PO) that engaged 2-300 mols contraction or an amide, and the like C ₁ -C ₂₅ alkoxylated phosphoric acid (salt).

The C ₁ -C ₂₀ alkanol addition condensation of the above ethylene oxide (EO) and / or propylene oxide (PO), methanol, ethanol, n- butanol, t-butanol, n- hexanol, octanol, decanol, lauryl alcohol, tetra Examples include decanol, hexadecanol, stearyl alcohol, eicosanol, oleyl alcohol, docosanol and the like. Similarly, examples of the bisphenols include bisphenol A, bisphenol B, and bisphenol F. Examples of the (poly) C ₁ -C ₂₅ alkylphenol include mono-, di-, or trialkyl-substituted phenols such as p-methylphenol, p-butylphenol, p-isooctylphenol, p-nonylphenol, p-hexylphenol, 2, Examples include 4-dibutylphenol, 2,4,6-tributylphenol, dinonylphenol, p-dodecylphenol, p-laurylphenol, and p-stearylphenol. Examples of the arylalkylphenol include 2-phenylisopropylphenol, cumylphenol, (mono, di or tri) styrenated phenol, (mono, di or tri) benzylphenol and the like. Examples of the alkyl group of the C ₁ -C ₂₅ alkyl naphthol include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, octadecyl and the like, and may be at any position of the naphthalene nucleus. Examples of the polyalkylene glycol include polyoxyethylene glycol, polyoxypropylene glycol, and polyoxyethylene polyoxypropylene copolymer.

The C ₁ -C ₂₅ alkoxylated phosphoric acid (salt) is represented by the following general formula (a).
Ra, Rb, (MO) P = O (a)
(In the formula (a), Ra and Rb are the same or different C ₁ -C ₂₅ alkyl, provided that one of them may be H. M represents H or an alkali metal.)

Examples of the sorbitan ester include mono-, di- or triesterized 1,4-, 1,5- or 3,6-sorbitan such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan distearate, sorbitan dioleate And sorbitan mixed fatty acid ester. Examples of the C _{1 to} C ₂₂ aliphatic amine include saturated and unsaturated fatty acids such as propylamine, butylamine, hexylamine, octylamine, decylamine, laurylamine, myristylamine, stearylamine, oleylamine, beef tallow amine, ethylenediamine, and propylenediamine. An amine etc. are mentioned. Examples of the C ₁ -C ₂₂ aliphatic amide include amides such as propionic acid, butyric acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid, coconut oil fatty acid, and beef tallow fatty acid. Is mentioned.

Furthermore, as the nonionic surfactant,
R ₁ N (R ₂ ) ₂ → O
(In the above formula, R ₁ represents C _{5 to} C ₂₅ alkyl or RCONHR ₃ (R ₃ represents C _{1 to} C ₅ alkylene), R ₂ represents the same or different C _{1 to} C ₅ alkyl) and the like. Amine oxides can be used.

As the cationic surfactant, a quaternary ammonium salt represented by the following general formula (b)
_{(R 1 · R 2 · R} 3 · R 4 N) + · X - ... (b)
(In the formula (b), X is halogen, hydroxy, C ₁ -C ₅ alkanesulfonic acid or sulfuric acid, R ₁ , R ₂ , R ₃ and R ₄ are the same or different C ₁ -C ₂₀ alkyl, aryl or benzyl. Or a pyridinium salt represented by the following general formula (c).
R _6- (C ₅ H ₄ N-R ₅ ) ⁺ · X ⁻ (c)
(In the formula (c), C ₅ H ₄ N is a pyridine ring, X is halogen, hydroxy, C ₁ -C ₅ alkanesulfonic acid or sulfuric acid, R ₅ is C ₁ -C ₂₀ alkyl, R ₆ is H or C _1. ~C ₁₀ represents an alkyl.)

  Examples of cationic surfactants in the form of salts include lauryl trimethyl ammonium salt, stearyl trimethyl ammonium salt, lauryl dimethyl ethyl ammonium salt, octadecyl dimethyl ethyl ammonium salt, dimethyl benzyl lauryl ammonium salt, cetyl dimethyl benzyl ammonium salt, octadecyl dimethyl Benzylammonium salt, trimethylbenzylammonium salt, triethylbenzylammonium salt, dimethyldiphenylammonium salt, benzyldimethylphenylammonium salt, hexadecylpyridinium salt, laurylpyridinium salt, dodecylpyridinium salt, stearylamine acetate, laurylamine acetate, octadecylamine acetate, etc. Is mentioned.

  Examples of the anionic surfactant include alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, alkyl benzene sulfonates, {(mono, di, tri) alkyl} naphthalene sulfonates, etc. Is mentioned. Examples of the alkyl sulfate include sodium lauryl sulfate and sodium oleyl sulfate. Examples of the polyoxyethylene alkyl ether sulfate include sodium polyoxyethylene (EO5) nonyl ether sulfate and sodium polyoxyethylene (EO15) dodecyl ether sulfate. Examples of the polyoxyethylene alkylphenyl ether sulfate include polyoxyethylene (EO15) nonylphenyl ether sulfate. Examples of the alkyl benzene sulfonate include sodium dodecylbenzene sulfonate. Examples of the {(mono, di, tri) alkyl} naphthalene sulfonate include naphthalene sulfonate, sodium dibutyl naphthalene sulfonate, and naphthalene sulfonate formalin condensate.

  Examples of the amphoteric surfactant include carboxybetaine, imidazoline betaine, sulfobetaine, and aminocarboxylic acid. In addition, sulfation of a condensation product of ethylene oxide and / or propylene oxide and an alkylamine or diamine, or a sulfonated adduct can also be used.

  Representative carboxybetaines or imidazoline betaines are lauryldimethylaminoacetic acid betaine, myristyldimethylaminoacetic acid betaine, stearyldimethylaminoacetic acid betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, 2-undecyl-1-carboxymethyl-1 -Hydroxyethyl imidazolinium betaine, 2-octyl-1-carboxymethyl-1-carboxyethyl imidazolinium betaine, and the like. Sulfated and sulfonated adducts include sulfated adducts of ethoxylated alkylamines, sulfonated Examples thereof include lauric acid derivative sodium salt.

  Examples of the sulfobetaines include coconut oil fatty acid amidopropyldimethylammonium-2-hydroxypropanesulfonic acid, sodium N-cocoylmethyl taurate, and sodium N-palmitoylmethyl taurate. Examples of the aminocarboxylic acid include dioctylaminoethylglycine, N-laurylaminopropionic acid, octyldi (aminoethyl) glycine sodium salt, and the like.

  Among the above surfactants, preferred nonionic surfactants include PEG, α-naphthol polyethoxylate (EO 10 mol), a copolymer of ethylene oxide (EO 18 mol) and propylene oxide (PO 20 mol), and a preferable cationic surfactant. As lauryltrimethylammonium salt, and preferred amphoteric surfactants include lauryldimethylaminoacetic acid betaine.

Nitrogen-based organic compounds mainly composed of the above dyes include dyes or derivatives thereof, amide compounds, thioamide compounds, compounds having an aniline or pyridine ring, various heterocyclic monocyclic compounds, various condensed heterocyclic compounds, Aminocarboxylic acids and the like.
Specific examples include CI (Color Index) basic red 2, toluidine dyes such as toluidine blue, azo dyes such as CI direct yellow 1 and CI basic black 2, 3-amino- Phenazine dyes such as 6-dimethylamino-2-methylphenazine monohydrochloride, imidazolines such as succinimide, 2'-bis (2-imidazoline), imidazoles, benzimidazoles, indoles, 2-vinylpyridine, Pyridines such as 4-acetylpyridine, 4-mercapto-2-carboxylpyridine, 2,2'-bipyridyl and phenanthroline, quinolines, isoquinolines, thioureas such as aniline, thiourea and dimethylthiourea, 3,3 ' , 3 ″ -nitrilotripropionic acid, diaminomethyleneaminoacetic acid, glycine, N-methyl Rugurishin, dimethylglycine, beta-alanine, cysteine, glutamic acid, aspartic acid, amino acid, such as ornithine.
Preferred examples include CI Basic Red 2, Yanas Green B, Toluidine Blue, and succinimide.

  Examples of the brightener include thiourea or derivatives thereof, mercaptans such as 2-mercaptobenzimidazole and thioglycolic acid, sulfides such as 2,2′-thiodiglycolic acid and diethyl sulfide, and 3-mercaptopropane-1- Examples thereof include mercaptosulfonic acids such as sodium sulfonate and bis (3-sulfopropyl) disulfide (disodium salt) (hereinafter referred to as SPS).

  As described above, chloride means a compound that has a function of accelerating the brightening and smoothing action of the brightener and leveler and can supply chlorine ions. Examples thereof include inorganic substances such as sodium chloride, potassium chloride, ammonium chloride, hydrochloric acid and copper chloride, and chlorinated organic compounds such as quaternary alkyl ammonium chloride and chloroacetic acid.

The electrolytic copper plating baths of the present invention 1 to 8 are effective in achieving both uniform electrodeposition and via filling. Therefore, the present invention 9 is a method of copper plating on an object to be plated (substrate) in which via holes and through holes are mixed using these electric copper plating baths.
The conditions for copper plating are arbitrary and there are no particular restrictions. Therefore, the anode may be a soluble anode made of copper (alloy) or an insoluble anode made of platinum or carbon.
In general, when copper is replenished by supplying copper ions to the plating tank by supplying a copper soluble anode during energization, the copper surface area gradually decreases, making it difficult to maintain a constant surface area, and the composition of the plating bath varies. In addition, there are problems such as uneven current density distribution and generation of anode slime. Therefore, if an insoluble anode is placed in the plating tank, and the copper ion that has been electrolyzed by anodic electrolysis can be supplied to the plating tank in a replenishment tank that is separate from the plating tank, there is no change in the shape of the anode, and bath management of the plating tank is easy. In addition, there is an advantage that slime generation at the anode can be prevented. However, when electroplating is performed in this replenishing tank method, additives such as levelers and brighteners contained in the copper plating bath are easily decomposed by the insoluble anode, so that the anode chamber is formed with an ion exchange membrane (anion and cation). It is preferable that the additive is prevented from moving to the insoluble anode, and only the movement of electrons is allowed.
In the present invention, any method of electrolytic copper plating using the above-described soluble anode or electrolytic copper plating using a combination of an insoluble anode and a replenishing tank can be applied.

Hereinafter, examples of the electrolytic copper plating bath of the present invention, each of the evaluation test examples of the uniform electrodeposition by the hull cell test using the plating bath and the uniform electrodeposition at the through hole will be sequentially described.
The present invention is not limited to the following examples and test examples, and it is needless to say that arbitrary modifications can be made within the scope of the technical idea of the present invention.

<< Example of an electrolytic copper plating bath >>
Among Examples 1 to 13, Examples 1 to 3 are examples (corresponding to the present invention 1) containing a specific complexing agent in an inorganic acid bath (sulfuric acid bath), and Examples 1 and 3 are specific fats. Example 2 containing an aromatic thioaminocarboxylic acid (A) as a complexing agent, Example 2 is an example containing a specific aliphatic mercaptocarboxylic acid. Examples 4 to 13 are examples (corresponding to the present invention 2) containing a specific complexing agent in an organic acid bath, and Examples 4 to 7 are specific aliphatic thioaminocarboxylic acids (a). Example containing methionine as complexing agent, Example 8 containing cysteine as specific aliphatic thioaminocarboxylic acid (a), Example 9 containing mercaptosuccinic acid as specific aliphatic mercaptocarboxylic acid (b) Example of acid content, Example 10 contains thiodiglycol, which is a specific aliphatic sulfide (c), Example 11 shows 3,6-dithiaoctane-1, which is a specific aliphatic sulfide (d), Example of containing 8-diol, Example 12 is a containing example of thiourea (e), and Example 13 is a containing example of DTPA which is a specific aminocarboxylic acid (f). In the organic acid baths of Examples 4 to 13, Examples 4 to 5, 8 to 9 and 13 are examples in which the base acid is glycolic acid, Examples 6 and 12 are examples of MSA, and Examples 7 and 10 to 11 are used. Is an example of isethionic acid.
On the other hand, of Comparative Examples 1 to 7, Comparative Example 1 is an example of a conventionally known copper sulfate bath (that is, it does not contain any complexing agent including the specific complexing agent of Invention 1). Comparative Example 2 is an example of a copper bath containing DTPA as a complexing agent and using sulfuric acid as a base acid in accordance with Patent Documents 1 to 3 described above. Comparative Example 3 is an example of a copper bath containing thiourea based on Patent Documents 9 to 10 described above and using sulfuric acid as a base acid. Comparative Example 4 is an example of a copper bath containing cysteine according to the aforementioned Patent Document 5 and containing sulfuric acid as a base acid. Comparative Example 5 is an example of a copper bath containing thiodiglycol based on Patent Document 6 described above and using sulfuric acid as a base acid. Comparative Example 6 is an example of a copper bath containing MSA as a base acid without any complexing agent including the specific complexing agent of Invention 2. Comparative Example 7 is an example of a copper bath containing MSA as a base acid and containing a complexing agent (ethanolamine; conforming to Patent Document 1 described above) other than the specific one of Invention 2.
In addition, about each copper plating bath of an Example and a comparative example, each kind and content of copper salt and an acid were put together in the column of the left half part of FIG. 1 (the unit M of a density | concentration represents mol / L).

First, an electrolytic copper plating bath having a standard composition is shown below.
[Electric copper plating bath with standard composition]
Soluble copper salt (as Cu ion) 0.8mol / L
Acid 0.5 mol / L
PEG (average molecular weight 2000) 10ppm
Janus Green B 10ppm
SPS 10ppm
Chloride ion 10ppm
The electroplating bath has a plating temperature of 25 ° C. and a cathode current density of 2 A / dm ² .

(1) Example 1
Based on the above-described standard plating bath (hereinafter referred to as standard plating bath), copper sulfate is used as a soluble copper salt and sulfuric acid is used as an acid, and 1.0 mol / L of methionine is added as a complexing agent. An electric copper plating bath was constructed.

(2) Example 2
Based on the above standard plating bath, copper sulfate was used as the soluble copper salt and sulfuric acid was used as the acid, and 1.0 mol / L of mercaptosuccinic acid was added as a complexing agent, and an electrolytic copper plating bath was constructed. .

(3) Example 3
Based on the above standard plating bath, copper sulfate (content reduced from 0.8 mol / L to 0.3 mol / L) in soluble copper salt, sulfuric acid (content from 0.5 mol / L to 1) in acid In addition, an electrolytic copper plating bath was constructed by adding 0.45 mol / L of methionine as a complexing agent.

(4) Example 4
Based on the above standard plating bath, copper (II) oxide (divalent copper oxide in the following examples and comparative examples) is used as a soluble copper salt, glycolic acid is used as an acid, and methionine as a complexing agent. Of 1.0 mol / L, an electrolytic copper plating bath was constructed.

(5) Example 5
Based on the standard plating bath, copper oxide (content is reduced from 0.8 mol / L to 0.3 mol / L) and soluble acid is glycolic acid (content from 0.5 mol / L). (Increase to 1.0 mol / L) and 0.45 mol / L of methionine as a complexing agent were used to build an electrolytic copper plating bath.

(6) Example 6
Based on the above standard plating bath, copper oxide was used as the soluble copper salt, MSA was used as the acid, and 1.0 mol / L of methionine was added as a complexing agent, and an electrolytic copper plating bath was constructed.

(7) Example 7
Based on the standard plating bath, copper oxide was used as the soluble copper salt, and isethionic acid was used as the acid, and 1.0 mol / L of methionine was added as a complexing agent, and an electrolytic copper plating bath was constructed.

(8) Example 8
Based on the above standard plating bath, copper oxide was used as the soluble copper salt and glycolic acid was used as the acid, and 1.0 mol / L of cysteine was added as a complexing agent, and an electrolytic copper plating bath was constructed.

(9) Example 9
Based on the above standard plating bath, copper oxide is used as a soluble copper salt, glycolic acid is used as an acid, and 1.0 mol / L of mercaptosuccinic acid is added as a complexing agent. did.

(10) Example 10
Based on the above standard plating bath, copper oxide is used as the soluble copper salt, and isethionic acid is used as the acid, and 1.0 mol / L of thiodiglycol is added as a complexing agent, thereby constructing an electrolytic copper plating bath. did.

(11) Example 11
Based on the standard plating bath, copper oxide is used as the soluble copper salt and isethionic acid is used as the acid, and 3,6-dithiaoctane-1,8-diol (hereinafter referred to as DTOD) is used as the complexing agent. An electrolytic copper plating bath was erected with a mol / L content.

(12) Example 12
Based on the above standard plating bath, copper oxide was used as a soluble copper salt, MSA was used as an acid, and 1.0 mol / L of thiourea was added as a complexing agent, thereby constructing an electrolytic copper plating bath.

(13) Example 13
Based on the above standard plating bath, copper oxide was used as a soluble copper salt, glycolic acid was used as an acid, and 1.0 mol / L of DTPA was contained as a complexing agent, thereby constructing an electrolytic copper plating bath.

(14) Comparative Example 1
Based on the standard plating bath, an electrolytic copper plating bath was constructed using copper sulfate as the soluble copper salt and sulfuric acid as the acid.

(15) Comparative example 2
Based on the standard plating bath, copper sulfate was used as the soluble copper salt and sulfuric acid was used as the acid, and 1.0 mol / L of DTPA was added as a complexing agent, and an electrolytic copper plating bath was constructed.

(16) Comparative Example 3
Based on the above standard plating bath, copper sulfate was used as the soluble copper salt and sulfuric acid was used as the acid, and 1.0 mol / L of thiourea was added as a complexing agent, and an electrolytic copper plating bath was constructed.

(17) Comparative example 4
Based on the above standard plating bath, copper sulfate was used as the soluble copper salt and sulfuric acid was used as the acid, and 1.0 mol / L of cysteine was added as a complexing agent, and an electrolytic copper plating bath was constructed.

(18) Comparative Example 5
Based on the above standard plating bath, copper sulfate was used as the soluble copper salt, and sulfuric acid was used as the acid, and 1.0 mol / L of thiodiglycol was added as a complexing agent, and an electrolytic copper plating bath was constructed. .

(19) Comparative Example 6
Based on the standard plating bath, an electrolytic copper plating bath was constructed using copper oxide as the soluble copper salt and MSA as the acid.

(20) Comparative Example 7
Based on the above standard plating bath, copper oxide was used as the soluble copper salt and MSA was used as the acid, and 1.0 mol / L of ethanolamine was added as a complexing agent to construct an electrolytic copper plating bath.

Therefore, a hull cell test was performed using each of the copper electroplating baths of Examples 1 to 13 and Comparative Examples 1 to 7, and the throwing power was evaluated.
《Example of evaluation test of throwing power by Hull cell test》
That is, using an iron Hull cell plate, copper plating is performed while energizing under the condition of 1A-5 minutes-no stirring, and the films are 1.0 cm, 3.5 cm, 6.0 cm, and 8.5 cm from the high current end. The thickness was measured with a fluorescent X-ray film thickness meter, and the ratio T (%) of uniform electrodeposition between two different points was calculated based on the following Field formula. The combination of two different points was 6.0 / 8.5 → P4.5, 3.5 / 8.5 → P10, 1.0 / 8.5 → P22.
[Field expression]
T (%) = 100 (PM) / (PM-2)
T: Uniform electrodeposition P: Primary current distribution ratio between two points M: Ratio of plating film thickness between two points (However, the distribution of primary current density on the cathode of the hull cell is i = I (5.10− 5.24 logL) i: current density (A / dm ² ), I: total current (A), L: distance from the high current density side end (cm); The ratio of the current density of each is a numerical value of each primary current density distribution ratio P (P4.5, P10, P22), and the ratio of the plating film thickness at the measurement point by the combination is a numerical value of M.)

The middle column on the right side of FIG. 1 shows the test results of the throwing power divided into P4.5, P10, and P22.
Theoretically, in the primary current distribution ratio P, the numerical value is improved in the order of P4.5 <P10 <P22, and the uniform electrodeposition can be evaluated for each fixed P value between two points. The following evaluation was performed based on the comparison between the example corresponding to the item of P22 and the comparative example, but the same tendency was shown in P4.5 and P10.
Conventional electrodeposition (P22) of Comparative Example 1 using sulfuric acid as a base acid (not containing a complexing agent) is 37.7%, and Comparative Example using MSA as a base acid without containing a complexing agent 6 was 40.0%, but the throwing power of Examples 1 to 13 was 44.4 to 73.0% (P22). In the uniform electrodeposition of the examples, in Examples 1 and 3 to 7 in which methionine is a complexing agent, regardless of the type of the base acid (that is, regardless of the inorganic acid bath and the organic acid bath), 60% A numerical value before, after, or higher is shown. Of these, Example 3 (sulfuric acid bath) and Example 5 (glycolic acid bath) with high acid concentrations show high frequency values, and in particular, Example 5 shows 70%. The above is shown. As a general guideline, 70% or more at P22 is a very good value.
Therefore, regardless of the type of base acid, a copper plating bath containing the specific complexing agent of the present invention, or a copper plating bath containing a specific complexing agent with an organic acid as the base acid, is a uniform electrodeposition. From the standpoint of sex, it showed a significant advantage over Comparative Example 1 or 6 containing no complexing agent.

The uniform electrodeposition of Comparative Examples 2 to 5 containing DTPA, thiourea, cysteine, or thiodiglycol in accordance with the above-mentioned patent document in a conventional copper sulfate bath is only 33.8 to 38.8%. There was no significant difference from the throwing power (37.7%) of the conventional copper sulfate bath (Comparative Example 1) containing no complexing agent, or a low numerical value.
On the other hand, in Examples 1 to 3 containing methionine or mercaptosuccinic acid as a complexing agent in a copper sulfate bath, the uniform electrodeposition shows a high numerical value (50.1 to 63.1%). Examples 1 and 3 containing methionine showed excellent values of around 60%. In Examples 4 to 7 which contain methionine as a complexing agent and base acid is an organic acid such as glycolic acid, MSA or isethionic acid, the uniform electrodeposition is about 60% or more. It was.
As a result, in conventional copper sulfate baths and electro copper plating baths based on inorganic acids, in order to exert an excellent effect in terms of throwing power, methionine, mercaptosuccinic acid, etc. It was important to selectively contain a specific complexing agent, and it was confirmed that the effect could not be expected with other complexing agents such as DTPA, thiourea, cysteine, or thiodiglycol.
In addition, when a specific complexing agent such as methionine or mercaptosuccinic acid is contained, it exhibits excellent throwing power even in a copper plating bath using not only an inorganic acid but also an organic acid as a base acid (that is, , Regardless of the type of base acid).

Next, the copper bath of organic acid will be described in detail. As described above, organic acid baths (Examples 3 to 7, 9, and 11) containing a specific complexing agent such as methionine, mercaptosuccinic acid, or DTOD exhibited excellent throwing power.
On the other hand, when the complexing agents (cysteine, thiourea, etc.) disclosed in the aforementioned patent document, which did not improve the throwing power even when contained in a conventional copper sulfate bath, were studied, Compared to Comparative Example 4 containing cysteine, Example 8 containing cysteine in a copper bath of glycolic acid showed a marked improvement in the throwing power (36.7% → 57.2%). In contrast to Comparative Example 5 in which the copper sulfate bath contained thiodiglycolic acid, there was also a clear improvement in Example 10 in which the copper bath of isethionic acid contained thiodiglycol (38.8% → 47 0.0%). Furthermore, a copper sulfate bath containing DTPA (Comparative Example 2) and an organic acid bath (Example 13), or a copper sulfate bath containing thiourea (Comparative Example 3) and an organic acid bath (Example 12). In contrast, similarly, the organic acid bath has a clear advantage over the inorganic acid bath (copper sulfate bath) in terms of throwing power. Thus, even if it is in a complexing agent such as cysteine, thiourea, DTPA and the like that cannot be expected to improve the effect of uniform electrodeposition when contained in an inorganic acid bath, it can be added to the organic acid bath (that is, organic In combination with an acid bath), it is possible to effectively improve the throwing power, and therefore the range (type) of complexing agents that can ensure the effectiveness of the improvement is more It was confirmed that it was wider than the combination. In other words, in the organic acid bath, even if the complexing agent to be contained is expanded to various types, the uniform electrodeposition property of the copper film obtained from the plating bath can be effectively improved.

Therefore, the throwing power of Examples 1 to 13 is evaluated in detail.
Comparing Example 4 (containing methionine) and Example 8 (containing cysteine), which have the same acid concentration and complexing agent concentration and are both glycolic acid baths, the methionine-containing bath (Example 4) is more uniform. The electrodeposition showed a high numerical value, and the same tendency was shown in the comparison between Example 6 (containing methionine) and Example 12 (containing thiourea) common in the MSA bath.
That is, when methionine was selected as the complexing agent, it was generally excellent in evaluating the throwing power regardless of the organic acid bath or the inorganic acid bath. In addition, when Examples 1, 4, and 6 to 7 containing the same methionine but having the same acid concentration and the same complexing agent concentration are different, the bath containing glycolic acid as a base acid (Example 4). ) Showed the highest value in the throwing power, and it was confirmed that the throwing power could be improved better by combining glycolic acid with methionine.
Furthermore, Example 5 (glycolic acid bath) and Example 3 (bath based on sulfuric acid) containing methionine are both baths with high acid concentration called high-throw baths. Evaluation was 73.0% in Example 5 and 63.1% in Example 3, indicating a very high value. Therefore, it can be estimated that the uniform electrodeposition improves as the acid concentration increases.
On the other hand, in Examples 9 and 8 containing mercaptosuccinic acid and cysteine, the evaluation was based on the methionine-containing bath in terms of throwing power, and complexing agents such as DTOD, DTPA, thiodiglycol, and thiourea Even in a bath containing, a clear improvement in uniform electrodeposition was recognized as compared with the comparative example. For example, when Example 12 (containing thiourea) and Comparative Example 7 (containing ethanolamine), both of which are based on MSA, are compared (acid concentration and complexing agent concentration are the same), as shown in the present invention, complexing agent is used. It is confirmed that the specification of this type (that is, specification to thiourea, not ethanolamine, etc.) is important for improving the throwing power.

<Example of uniform electrodeposition evaluation test using through-holes>
A glass / epoxy substrate having a through hole diameter of 0.4 mm and a plate thickness of 2.0 mm, which was subjected to Pd catalytic activity according to a conventional method and subjected to thin electroless copper plating, was used as a test piece.
After electroplating the test piece using each of the copper plating baths of Examples 1 to 13 and Comparative Examples 1 to 7, the center of the through hole was cut in the axial direction, and the plating thickness at the end of the through hole (T ₁ ) And the plating thickness (T ₂ ) at the center of the through hole were measured with a microscope, and the uniform electrodeposition T (%) was calculated by the following equation.
T (%) = (T ₂ / T ₁ ) × 100
The electrolytic copper plating conditions were the same as those shown in the standard plating bath column.

The second column from the right in FIG. 1 shows the test results.
Although the uniform electrodeposition property in the through holes of Comparative Examples 1-7 is 76-81%, in Examples 1-13, it is a numerical value of 90% or more, and showed the remarkable advantage over the Comparative Example.
In general, in the evaluation of the throwing power on the through hole, about 90% is a high-throw bath with a high acid concentration and about 70 to 80% is a general bath, but the inorganic acid bath is made of methionine or mercaptosuccinic acid. In an example in which the organic acid bath contains a specific complexing agent such as methionine, mercaptosuccinic acid, DTOD, and thiourea (various from those of the inorganic acid bath), Since all achieved a numerical value of 90% or more, it was confirmed that the electrodepositability at the through hole was excellent. Of these, in the examples of the organic acid (glycolic acid, MSA, isethionic acid) bath using methionine as a complexing agent or the glycolic acid bath using mercaptosuccinic acid or cysteine as a complexing agent, both are 95% or more. It was confirmed that it was particularly excellent in throwing power on the through-hole.
Examples 1 and 3 and Examples 4 and 5 both have the same kind of complexing agent (methionine) and acid but different acid concentrations (0.5 mol / L → 1.0 mol / L). However, from these comparisons, it can be confirmed that, in a high-throw bath with a high acid concentration, the throwing power is naturally improved.
As described above, the copper plating bath of the inorganic acid or organic acid containing the specific complexing agent of the present invention is more remarkable than the conventionally known copper sulfate bath or the copper bath of organic acid not containing the specific complexing agent. It was confirmed that the electrodeposition was excellent in throwing power, particularly throwing through holes.

  Therefore, when the copper plating bath of the present invention (for example, Example 4) was applied to a substrate having a via hole instead of the substrate having the through hole, it was confirmed that there was a good via filling ability. Therefore, when the copper plating bath of the present invention is applied to a substrate in which via holes and through holes are mixed, it can be expected that copper filling in via holes and uniform electrodeposition in through holes can be achieved at the same time. As described above, the via filling is mechanically different from the uniform electrodeposition, and the reason why it exhibits a good via filling ability is unknown at the present time, while exhibiting excellent uniform electrodeposition.

The composition of each copper electroplating bath of Examples 1-13 and Comparative Examples 1-7, the result of each evaluation test of the uniform electrodeposition by the hull cell test using the said plating bath, and the uniform electrodeposition in a through hole are shown. It is a chart.

Claims (9)

In an electrolytic copper plating bath containing a soluble copper salt, a base acid and a complexing agent,
The complexing agent is at least one of the following compounds (A) to (E)
(A) an aliphatic thioaminocarboxylic acid or a salt thereof selected from the group consisting of methionine, ethionine, cystine, and N-acetylcysteine
(B) an aliphatic mercaptocarboxylic acid selected from the group consisting of mercaptoisobutyric acid, mercaptoacetic acid, dimercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, mercaptosuccinic acid, and 2,3-dimercaptosuccinic acid, or Its salt
(C) Sulfides represented by the following general formula (1) Ra- (A) j-S- (B) k-Rb (1)
(In the formula (1), j and k are integers of 1 to 100; A and B may be the same or different, and methylene, ethylene, 1,3-propylene, 1,2-propylene, 1,4, respectively. -Butylene, 1,2-butylene, 1,3-butylene, or these C ₂ -C ₄ oxyalkylenes; Ra and R b may be the same or different and each is H (where A and B are both methylene) In the case of C ₂ -C ₄ alkylene, either Ra or R b is not H. Also, when both A and B are C ₂ -C ₄ oxyalkylene, when j and k are both 1, Ra And Rb are not H.), OH, NH ₂ , CO ₂ M, SO ₃ M, pyridyl group or aminophenyl group; M is an alkali metal, alkaline earth metal, ammonium or amine)
(D) the following general formula sulfides represented by (2) Ra-S- (CH 2 CH 2 -S) n-Rb ... (2)
(In the formula (2), n is an integer of 1 to 3; Ra and Rb may be the same or different, and are each — (CH ₂ ) m —R c; m is an integer of 0 or 1 to 5; There; Rc is a pyridyl group or an aminophenyl group when m is 0, when m is an integer from 1 to 5 be _{OH, NH 2, CO 2 M} , SO 3 M, pyridyl or aminophenyl group M is an alkali metal, alkaline earth metal, ammonium or amine)
(E) A thiourea derivative represented by the following general formula (3) Rd—NH—C (═S) —NH—Re (3)
(In the formula (3), Rd and Re may be the same or different and each is — (CH ₂ ) p—Rf; p is an integer of 2 to 5; Rf is a pyridyl group)
An electrolytic copper plating bath characterized by In an electrolytic copper plating bath containing a soluble copper salt, a base acid and a complexing agent,
The base acid is an organic acid or a salt thereof, and the complexing agent is at least one of the following compounds (a) to (f) (provided that the base acid is tartaric acid, citric acid or a salt thereof, Is a compound (a) to (e) or a compound (f) excluding ethylenediaminetetraacetic acid)
(a) an aliphatic thioaminocarboxylic acid or a salt thereof selected from the group consisting of methionine, ethionine, cystine, N-acetylcysteine and cysteine
(b) an aliphatic mercaptocarboxylic acid selected from the group consisting of mercaptoisobutyric acid, mercaptoacetic acid, dimercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, mercaptosuccinic acid, and 2,3-dimercaptosuccinic acid, or Its salt
(c) Sulfides represented by the following general formula (1) Ra- (A) j-S- (B) k-Rb (1)
(In the formula (1), j and k are integers of 1 to 100; A and B may be the same or different, and methylene, ethylene, 1,3-propylene, 1,2-propylene, 1,4, respectively. -Butylene, 1,2-butylene, 1,3-butylene, or these C ₂ -C ₄ oxyalkylenes; Ra and R b may be the same or different and each is H (where A and B are both methylene) In the case of C ₂ -C ₄ alkylene, one of Ra and R _b is not H), OH, NH ₂ , CO ₂ M, SO ₃ M, a pyridyl group or an aminophenyl group; M is an alkali metal, (Alkaline earth metal, ammonium, amine)
(d) the following general formula sulfides represented by (2) Ra-S- (CH 2 CH 2 -S) n-Rb ... (2)
(In the formula (2), n is an integer of 1 to 3; Ra and Rb may be the same or different, and are each — (CH ₂ ) m —R c; m is an integer of 0 or 1 to 5; There; Rc is a pyridyl group or an aminophenyl group when m is 0, when m is an integer from 1 to 5 be _{OH, NH 2, CO 2 M} , SO 3 M, pyridyl or aminophenyl group M is an alkali metal, alkaline earth metal, ammonium or amine)
(e) At least one of thiourea and thiourea derivatives
(f) Hydroxyethylethylenediaminetriacetic acid, N, N-dicarboxymethyl-L-glutamic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, glutamic acid, N, N-dicarboxymethyl-L-aspartic acid, diethylenetriaminepentaacetic acid, triethylenetetramine Hexaacetic acid, iminodiacetic acid, iminodipropionic acid, aspartic acid, hydroxyethylidene diphosphonic acid, nitrilotris (methylenephosphonic acid), phosphonobutanetricarboxylic acid, hydroxyethylaminodimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, N, N-dicarboxymethyl-L-alanine, 1,3-propanediaminetetraacetic acid, glycol ether diaminetetraacetic acid, ethylenediamine disuccinic acid, alanine, hydroxy An aminocarboxylic acid selected from the group consisting of ethyliminodiacetic acid, glycine, 1,3-diamino-2-hydroxypropanetetraacetic acid, ornithine, N, N-bis (2-hydroxyethyl) glycine, aminophosphonic acid, phosphonic acid, An electrolytic copper plating bath which is at least one of phosphonocarboxylic acid or a salt thereof.   The electrolytic copper plating bath according to claim 1 or 2, wherein the complexing agent is methionine.   The electrolytic copper plating bath according to claim 2 or 3, wherein the organic acid is oxycarboxylic acid or organic sulfonic acid.   The electrolytic copper plating bath according to claim 4, wherein the oxycarboxylic acid is glycolic acid.   The electrolytic copper plating bath according to claim 4, wherein the organic sulfonic acid is methanesulfonic acid or 2-hydroxyethanesulfonic acid.   The electrolytic copper plating bath according to claim 2, wherein the complexing agent is methionine and the organic acid is glycolic acid.   Furthermore, additives, such as a leveler and a brightener, are contained, The electrolytic copper plating bath of any one of Claims 1-7 characterized by the above-mentioned.   A copper plating film is formed on an object to be plated in which via holes and through holes are mixed, using the electrolytic copper plating bath according to any one of claims 1 to 8.

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