ULSI wiring and method of manufacturing the same
View Patent ↗A method of manufacturing ULSI wiring in which wiring layers are separately formed via a diffusion prevention layer and an insulating interlayer portion made of SiO 2 . The method comprises the steps of treating, with a silane compound, a SiO 2 surface of the insulating interlayer portion on which the diffusion layer is to be formed, performing catalyzation with an aqueous solution containing a palladium compound, forming the diffusion prevention layer by electroless plating, and then forming the wiring layer on this diffusion prevention layer. A capping layer may be formed on the wiring layer by electroless plating. Consequently, a diffusion prevention layer having good adhesive properties can be formed through a simple wet process, and, the wiring layer can directly be formed on this diffusion prevention layer by a wet process. The capping layer can also be directly formed on the wiring layer by electroless plating.
1. A method of manufacturing ULSI wiring in which wiring layers are separately formed via a single diffusion prevention layer formed on a surface of a hollowed portion of an insulating interlayer made of SiO 2 , said method comprising the steps of:
treating a SiO 2 surface on the hollowed portion of the insulating interlayer with an organic silane compound to form an organic silane monomolecular layer;
performing catalyzation of the treated SiO 2 surface with an aqueous solution containing a palladium compound;
thereafter forming the single diffusion prevention layer by a electroless plating method using a plating bath selected from the group consisting of an electroless nickel-tungsten-phosphorous bath, and an electroless nickel-rhenium-phosphorous bath, wherein in the nickel-tungsten-phosphorus bath and the nickel-rhenium-phosphorus bath the tungsten or rhenium content is 40-80 wt %, the phosphorous content is 0.1 to 1.0 wt %, and the residual is nickel; and
then forming the wiring layer on the single diffusion prevention layer.
2. The method according to claim 1 , wherein the single diffusion prevention layer is formed by a single-stage electroless plating method with the plating bath being in a neutral or acid condition.
3. The method according to claim 1 , further comprising:
forming a metallic core by use of a neutral or acid electroless plating bath after performing catalyzation and before forming the single diffusion layer.
4. The method according to claim 3 , wherein the neutral or acid electroless plating bath is an electroless nickel plating bath.
5. The method according to claim 1 , wherein the wiring layer is formed directly on the single diffusion prevention layer by use of electroless copper plating or electroplating with copper.
6. The method according to claim 1 , wherein the organic silane compound is a silane coupling agent having amino groups and alkoxy groups or a silane coupling agent having alkoxy groups and epoxy groups.
7. The method according to claim 1 , wherein the organic silane compound is selected from the group consisting of N-(2-aminoethyl)-3-aminopropyl trimethoxy silane, 3-aminopropyl trimethoxy silane, 2-(trimethoxysilyl)ethyl-2-pyridine, (aminoethyl)-phenethyl trimethoxy silane and γ-glycidyl propyl trimethoxy silane.
8. The method according to claim 1 , wherein the step of treating the SiO 2 surface of the insulating interlayer portion with the organic silane compound comprises
dissolving the organic silane compound in a solvent, and
dipping the insulating interlayer portion into the dissolved organic silane compound.
9. The method according to claim 8 , wherein dipping the insulating interlayer portion in the dissolved organic silane compound forms a self-organizing monomolecular layer in chemical bond with the SiO 2 surface.
10. The method according to claim 1 , wherein the wiring layer is formed directly on the single diffusion prevention layer without catalyzing the surface of the single diffusion prevention layer.
11. The method according to claim 1 , wherein the wiring layer comprises copper and is formed by electroless plating.
12. The method according to claim 11 , further comprising forming a capping layer directly on the wiring layer without catalyzing the surface of the single diffusion prevention layer.
13. The method according to claim 12 , wherein the capping layer comprises a metallic thin film and is formed by electroless plating.
14. The method according to claim 13 , wherein the capping layer is formed using the nickel-tungsten-phosphorous bath or the nickel-rhenium-phosphorous bath.
15. The method according to claim 1 , wherein the aqueous solution containing the palladium compound is an acidic solution.
16. The method according to claim 15 , wherein the acid aqueous solution containing the palladium compound has a pH set at 2 to 6.