Bath and method for filling a vertical interconnect access or trench of a work piece with nickel or a nickel alloy

Abstract

An aqueous bath for filling a vertical interconnect access or trench of a work piece with nickel or a nickel alloy, the bath comprising a source of nickel ions, and optionally a source of ions of at least one alloying metal, at least one buffering agent, at least one of a dimer of a compound of formula (I) or mixtures thereof ##STR00001## wherein R.sub.1 is a substituted or unsubstituted alkenyl group, R.sub.2 may be present or not, and if present R.sub.2 is a —(CH.sub.2).sub.n—SO.sub.3.sup.− group, wherein n is an integer in the range of 1-6, and wherein one or more of the hydrogens in the group may be replaced by a substituent, preferably hydroxide; and
a method for filling a vertical interconnect access or trench of a work piece with nickel or a nickel alloy with said aqueous bath.

Claims

1. An aqueous bath comprising a source of nickel ions, and optionally a source of ions of at least one alloying metal, at least one buffering agent, at least one of a dimer of a compound of formula (I) or mixtures thereof ##STR00011## wherein R.sub.1 is a substituted or unsubstituted alkenyl group, R.sub.2 may be present or not, so that the nitrogen may be positively charged or not, and R.sub.2, if present, is a —(CH.sub.2).sub.n—SO.sub.3.sup.− group, wherein n is an integer in the range of 1-6, wherein one or more of the hydrogens in the —(CH.sub.2).sub.n—SO.sub.3.sup.− group may be replaced by a substituent, wherein the at least one of a dimer of a compound of formula (I) or mixtures thereof comprises a compound of formula (II) ##STR00012##

2. The aqueous bath of claim 1, wherein the total concentration of the at least one of a dimer is 1-10000 mg/L.

3. The aqueous bath of claim 1, wherein the alloying metal is selected from cobalt or iron or a combination thereof.

4. An aqueous bath comprising a source of nickel ions, and optionally a source of ions of at least one alloying metal, at least one buffering agent, at least one of a dimer of a compound of formula (I) or mixtures thereof ##STR00013## wherein R.sub.1 is a substituted or unsubstituted alkenyl group, R.sub.2 may be present or not, so that the nitrogen may be positively charged or not, and R.sub.2, if present, is a —(CH.sub.2).sub.n—SO.sub.3.sup.− group, wherein n is an integer in the range of 1-6, wherein one or more of the hydrogens in the —(CH.sub.2).sub.n—SO.sub.3.sup.− group may be replaced by a substituent, wherein the compound of formula (I) comprises a compound of formula (III) ##STR00014##

5. The aqueous bath of claim 4, wherein the dimer of the compound of formula (III) is a compound of formula (IV) ##STR00015##

6. The aqueous bath of claim 4, wherein the total concentration of the at least one of a dimer is 1-10000 mg/L.

7. The aqueous bath of claim 4, wherein the alloying metal is selected from cobalt or iron or a combination thereof.

8. A compound of formula (II) ##STR00016## wherein R.sub.2 is a —(CH.sub.2).sub.n—SO.sub.3.sup.− group, wherein n is an integer in the range of 1-6, and wherein one or more of the hydrogens in the —(CH.sub.2).sub.n—SO.sub.3.sup.− group may be replaced by a substituent.

9. The compound of claim 8, which is a compound of formula (IV) ##STR00017##

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1: UV-Vis spectra of monomer and dimer;

(2) FIG. 2: IR spectrum of reaction mixture;

(3) FIG. 3: 1H-NMR-spectrum of reaction mixture;

(4) FIG. 4: 13C-NMR-spectrum of reaction mixture;

(5) FIG. 5: 2D-NMR-spectrum of reaction mixture;

(6) FIG. 6: LC/HPLC-NMR-spectrum of reaction mixture;

(7) FIG. 7: shows the filling of micro via (vertical interconnect access) with a Ni-bath with compound of formula (III) and with a dimer of formula (IV).

EXAMPLES

(8) The invention will now be illustrated by reference to the following non-limiting examples.

Example 1

Synthesis of a Dimer of a Compound of Formula (IV)

(9) 60 g of a compound of formula (III) were added to 40 g of water and heated to reflux for 96 h. A light brown solution was formed. Removal of the solvent gave 60 g of the dimer.

(10) Characterization of the product was made by UV-Vis, IR-Spectroscopy, 1H-NMR, 13C-NMR, two-dimensional-NMR (2D-NMR) and liquid chromatography (LC)/HPLC. The results are as follows:

(11) UV-Vis (LC-UV):

(12) Results are shown in FIG. 1 at the end of the reaction. UV-Vis is sensitive to the size of the aromatic π system: saturation of vinyl group during dimerization leads to a blue shift of the absorption maximum from 289 nm to 270 nm. This was qualitatively confirmed by electronic structure calculations. However, formation of other species with smaller π system could also lead to a blue shift, so that further methods for characterization were applied.

(13) IR:

(14) Results are shown in FIG. 2 at the end of the reaction. The method is sensitive to the vinyl group vibration mode around 950 cm.sup.−1, which is shown in FIG. 2. This was confirmed by electronic structure calculations. This method can be used for monitoring reaction progress. This method quantifies consumption of monomer, not explicitly formation of dimer, so that further methods for characterization were applied.

(15) 1H-NMR:

(16) Results are shown in FIG. 3 at the end of the reaction. The results confirm a loss of the vinyl group. The results moreover confirm 4+2 cycloaddition as opposed to 2+2 cycloaddition based on the balance of aromatic to aliphatic protons. The method is not specific enough to distinguish two 4+2 isomers, so that further methods were applied.

(17) 13C-NMR:

(18) Results are shown in FIG. 4 at the end of the reaction. Modeling the spectrum allows for preliminary structure identification, showing that a compound of formula (IV) (called “dimer 1”) is formed. “Dimer 2” is a compound of formula (VIII)

(19) 2D-NMR

(20) Results are shown in FIG. 5 at the end of the reaction. The results show that a compound of formula (IV) (called “dimer 1”) is formed.

(21) LC/HPLC:

(22) Results are shown in FIG. 6 at the end of the reaction. The results show that separation of monomer and dimer is possible. LC-UV confirms the UV spectra of individual peaks for the two substances (cf. supra). LC-MS confirms the M/z=455 peak corresponding to the dimer. The method allows qualitative observation only, quantification is not possible since some dimer could be formed in the gas phase as ionic complex, as observed for PPS reference (PPS=SPV-vinyl), which cannot form a chemical dimer by cycloaddition.

Example 2

(Comparative): Ni Bath with Compound of Formula (Ill)

(23) TSV substrate with 10×30 μm vias, 2 ASD (ampere per square decimeter), 10 min 50° C. 100 rpm stirring Standard Spherolyte Ni VMS bath (70 g/L Ni, 5 g/L Chloride) with boric acid reduced to 30 g/I, comprising a compound of formula (III). Amounts of the compound of formula (III) were between 115 mg/L-920 mg/L.

(24) The results are shown in FIG. 7, first line of pictures.

Example 3

(Inventive): Ni Bath with Dimer of Compound of Formula (IV)

(25) The same bath and conditions were employed as in Example 2, but a compound of formula (IV) was used as predominant additive, obtained according to example 1. Some compound of formula (III) was still present (about 10 weight-%, based on the total amount of (IV)).

(26) The results are shown in FIG. 7, second (lower) line of pictures. Less voids can be seen in the filling structure in comparison to example 2. Moreover, faster deposition and filling was observed in comparison to example 2.