JP2003041393A - Copper plating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plated film of stable properties without controlling a leveler content in a plating solution. SOLUTION: An electrolytic copper plating method comprises making the objective surface to be plated adsorb at least one leveling substance selected from the groups consisting of organic acid amide and amine compounds, and subsequently plating the surface in a copper plating solution which contains no substance belonging to the above groups.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a multilayer printed circuit board,
The present invention relates to a method for forming a copper wiring used for a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, electrolytic plating in which a via hole or a trench of a multilayer printed wiring board or a semiconductor wafer is filled with copper plating has been widely used.

Generally, the procedure for electrolytic copper plating is as follows. Printed circuit boards, insulating films on semiconductor wafers, etc.
When electrolytic copper is applied to a portion having no conductivity, a copper conductive layer is formed on the above portion by electroless copper plating or sputtering. Next, the surface on which the conductive layer is formed is plated in an electrolytic copper plating bath to deposit electrolytic copper and obtain a desired copper plating film.

Usually, additives called brighteners, carriers, levelers and the like are added to this copper plating bath in order to make the copper plating film uniform and improve the physical properties and appearance of the copper plating film. Has been done. The effect of these additives controls the precipitated crystals.

[0005]

Generally, in the electrolytic copper plating method, as described above, a brightener in the plating solution,
Plating is performed by adding additives called carriers and levelers.

[0006] Here, the additive called leveler has a great influence on the filling of holes and trenches, which have become more and more demanded in recent years, and therefore management thereof has become important. That is, in order to fill the trenches and holes without defects and control the surface shape to be flat or slightly raised, it is necessary to manage the leveler components.

However, the leveler is used as a CVS (Cyclic Voltammetry Strippi) which is generally used for additive analysis.
ng) method, it is difficult to distinguish it from the carrier. The reason is that the leveler concentration is lower than the carrier concentration, and the carrier often acts as an inhibitor that suppresses the plating reaction as in the leveler, and the signals during analysis often overlap.

An object of the present invention is to obtain stable plating film characteristics without controlling the leveler component in the plating solution.

[0009]

As a result of earnest research, the present inventor has found that by preliminarily imparting a specific leveler to the surface to be plated, it becomes unnecessary to manage the leveler component in the plating solution. That is, according to the present invention, the above problems are
Adsorbing at least one leveler substance selected from the group of organic acid amides and amine compounds on the surface to be plated,
After that, the problem is solved by an electrolytic copper plating method of plating in a copper plating solution containing no substance belonging to the above group. A carrier may be adsorbed together when the above substance is adsorbed on the surface to be plated.

The above-mentioned groups of organic acid amides and amine compounds are specifically acetamide, propylamide, benzamide, acrylamide, methacrylamide, N, N-.
Dimethylacrylamide, N, N-diethylmethacrylamide, N, N-diethylacrylamide, N, N-dimethylmethacrylamide, N- (hydroxymethyl) acrylamide, polyacrylic acid amide, polyacrylic acid amide hydrolyzate, thioflavin and Safranin, a chemical containing one or more of these, is applied to the surface to be plated. The carrier is, for example, carboxymethyl cellulose, nonylphenol polyglycol ether, octanediol-bis- (polyalkylene glycol ether), octanol polyalkylene glycol ether, polyethylene polypropylene glycol ether, polyethylene glycol, polyethylene glycol-dimethyl ether, polyoxypropylene glycol, polypropylene. Glycol, polyvinyl alcohol, stearic acid-polyglycol ester, β
Naphthol-polyglycol ether and stearylalkyl-polyglycol ether.

The copper plating solution is not particularly limited, and any kind of copper plating solution can be used as long as it can be used for electrolytic copper plating. The plating equipment may also be of a type that includes either a soluble anode or an insoluble anode. As described above, generally, a brightener, a carrier, and a leveler are conventionally added to the plating bath, but the copper plating solution according to the present invention contains an additive that does not correspond to the leveler of the organic acid amide or amine compound. There is no problem even if added. That is, in the copper plating solution according to the present invention, as a brightener component, 3- (benzothiazolyl-2-thio) propylsulfonic acid and its sodium salt, 3-mercaptopropane-1-sulfonic acid and its sodium salt, and ethylenedithio are used. Dipropyl sulfonic acid and its sodium salt,
Bis- (p-sulfophenyl) -disulfide and its disodium salt, bis- (w-sulfobutyl) -disulfide and its disodium salt, bis- (w-sulfohydroxypropyl) -disulfide and its disodium salt, bis- (w-Sulfopropyl) -disulfide and its disodium salt, bis- (w-sulfopropyl)
-Sulfide and its disodium salt, methyl- (w
-Sulfopropyl) -sulfide and its disodium salt, methyl- (w-sulfopropyl) -trisulfide and its disodium salt, thioglycolic acid, thiophosphoric acid-ortho-ethyl-bis- (w-sulfopropyl)-
Esters and their disodium salts, thiophosphoric acid-tris- (w-sulfopropyl) -esters and their disodium salts, thiophosphoric acid-tris- (w-sulfopropyl) -esters and their trisodium salts may be added. .

For adsorbing the leveler substance on the surface to be plated, an appropriate method such as dropping, dipping, spin coating, spraying or the like can be adopted. In the case of spin coating, rotate the excess leveler to shake it off. Even in other adsorption treatments, extra levelers should be removed by washing with pure water or the like. There is also no particular restriction on the concentration of the leveler and the carrier to be adsorbed, and it is determined in consideration of the appropriate amount of surface adsorption depending on the coating method. For example, the leveler is 0.01 g / liter or more and 1 g / liter or less, and the carrier is 0.3 g / liter or more 15
It is preferably g / liter or less.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail in the exemplary embodiments.

(Example 1) If necessary, a leveler was dropped and applied on the surface of a printed circuit board on which a conductive layer of copper was formed by electroless copper plating or sputtering on the non-conductive portion. The leveler referred to here is 0.016 g of safranine.
It is a liquid medicine containing / liter. After the adsorption, the surface of the substrate was washed with pure water to remove excess leveler. Next, as a brightener, 3-mercaptopropane-1-sulfonic acid was added to 0.2.
The above-mentioned printed circuit board was placed in an electrolytic copper plating bath containing 1 mg / liter and 0.4 g / liter of polypropylene glycol as a carrier for plating treatment. Here, the composition of the copper plating bath other than the additive is a copper ion concentration of 35 g /
Liter, sulfuric acid concentration 180 g / liter and chloride ion concentration 50 mg / liter. Then, phosphorus-containing copper was used as a soluble anode. Then, the plating solution on the plating surface was washed and dried to complete the plating process.

By the above process, the leveler can be independently adsorbed on the substrate surface without adding it to the plating bath.

(Example 2) As in Example 1, if necessary, a chemical solution was dropped and applied onto the surface of a printed circuit board on which a conductive layer of copper was formed by electroless copper plating or a sputtering method on the non-conductive portion. The chemical solution mentioned here contains 0.016 g / liter of safranine as a leveler and 0.4 g / liter of polypropylene glycol as a carrier. After the chemical solution was adsorbed, the substrate surface was washed with pure water to remove the excess chemical solution. Next, the printed board was placed in an electrolytic copper plating bath containing 0.1 mg / liter of 3-mercaptopropane-1-sulfonic acid as a brightener to perform plating treatment. The composition other than brightener in the copper plating bath was as follows: copper ion concentration 35 g / liter, sulfuric acid concentration 1
80 g / liter and a chloride ion concentration of 50 mg / liter. Then, phosphorus-containing copper was used as a soluble anode. Then, the plating solution on the plating surface was washed and dried to complete the plating process.

By the above process, the carrier and the leveler can be independently adsorbed on the substrate surface without adding to the plating bath. In the above description of the two examples, the leveler is limited to one type and the carrier is limited to one type, but it is also possible to apply it so as to include a plurality of types.

[0018]

According to the present invention, since the treatment is performed without adding the leveler to the plating bath, the leveler analysis in the plating bath, which has been performed so far, becomes unnecessary, and the management of the plating bath is greatly simplified. Despite such simplification, stable plating characteristics can be secured. If the carrier is also adsorbed in advance together with the leveler, the analysis of the additives in the plating bath only needs to be performed on the brightener, and the management of the plating bath is greatly simplified.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05K 3/18 H05K 3/18 G (72) Inventor Kinshi Kinkyu 1-18 Shirayama, Midori-ku, Yokohama-shi, Kanagawa Prefecture No. 2 Jerman Industry Center Attec Japan Co., Ltd. (72) Inventor Takumi Shigeta 1-2-18 Shirayama, Midori-ku, Yokohama-shi, Kanagawa F-Term (Jerman Industry Center Attec Japan Co., Ltd.) ) 4K023 AA19 BA06 BA07 CA01 CA02 CA09 CB07 CB15 CB17 4K024 AA09 AB02 AB15 AB17 BA12 BB11 BB12 BC10 DB10 GA16 5E343 AA02 AA11 AA39 BB16 BB24 BB71 CC22 CC78 DD23 DD33 DD43 EE32 GG06

Claims (2)

[Claims] 1. An electrolytic copper plating method, wherein acetamide, propylamide, benzamide, acrylamide,
Methacrylamide, N, N-dimethylacrylamide, N, N-diethylmethacrylamide, N, N-diethylacrylamide, N, N-dimethylmethacrylamide, N- (hydroxymethyl) acrylamide, polyacrylic acid amide, polyacrylic acid amide Hydrolyzate,
A plating method comprising adsorbing at least one substance selected from the group consisting of thioflavin and safranine on a surface to be plated, and then plating in a copper plating solution containing no substance belonging to the above group. 2. A carrier is also adsorbed at the time of adsorbing the substance onto the surface to be plated, and after adsorbing these, plating is performed in a copper plating solution containing neither the carrier nor any substance belonging to the above group. The plating method according to claim 1, wherein: