Electrolessly formed high resistivity magnetic materials

Patent metadata

Field	Value
Publication number	US-11152144-B2
Application number	US-201715486744-A
Country	US
Kind code	B2
Filing date	Apr 13, 2017
Priority date	May 2, 2016
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

Present disclosure relates to magnetic materials, chips having magnetic materials, and methods of forming magnetic materials. In certain embodiments, magnetic materials may include a seed layer, and a cobalt-based alloy formed on seed layer. The seed layer may include copper, cobalt, nickel, platinum, palladium, ruthenium, iron, nickel alloy, cobalt-iron-boron alloy, nickel-iron alloy, and any combination of these materials. In certain embodiments, the chip may include one or more on-chip magnetic structures. Each on-chip magnetic structure may include a seed layer, and a cobalt-based alloy formed on seed layer. In certain embodiments, method may include: placing a seed layer in an aqueous electroless plating bath to form a cobalt-based alloy on seed layer. In certain embodiments, the aqueous electroless plating bath may include sodium tetraborate, an alkali metal tartrate, ammonium sulfate, cobalt sulfate, ferric ammonium sulfate and sodium borohydride and has a pH between about 9 to about 13.

First claim

What is claimed is:

1. A method of making a magnetic structure comprising:
forming one or more conductive structures in a dielectric layer disposed over a substrate;
forming a seed layer on the dielectric layer, the seed layer comprising a cobalt-iron-boron alloy;
forming a bottom yoke on the cobalt-iron-boron alloy seed layer, the bottom yoke comprising an electroless plated cobalt-iron-boron alloy, the electroless plated cobalt-iron-boron alloy formed by placing the seed layer in an aqueous electroless plating bath, wherein the aqueous electroless plating bath comprises sodium tetraborate, an alkali metal tartrate, ammonium sulfate, cobalt sulfate, ferric ammonium sulfate, and sodium borohydride, and the aqueous electroless plating bath has a pH of about 11, wherein the sodium borohydride comprises a concentration in a range from about 5 micromoles per liter to about 200 micromoles per liter, and ranges therebetween, wherein the electroless plated cobalt-iron-boron alloy has a resistivity of up to about 1550 micro ohms centimeter, wherein the electroless plated cobalt-iron-boron alloy comprises boron in an atomic percentage of about 45%;
forming a dielectric encapsulation layer on a surface of the bottom yoke and a surface of the dielectric layer;
forming conductive coils on a surface of the dielectric encapsulation layer;
forming a hardbaked photoresist over the conductive coils, the hardbaked photoresist on the surface of the dielectric encapsulation layer; and
forming a top yoke over the hardbaked photoresist, wherein the top yoke is formed by an electroless plating process using the bottom yoke as a seed layer.

2. The method of claim 1 , wherein the sodium tetraborate comprises a concentration in a range from about 0.005 moles per liter to about 0.02 moles per liter, and ranges therebetween, the alkali metal tartrate comprises a concentration in a range from about 0.222 moles per liter to 0.250 moles per liter, and ranges therebetween, the ammonium sulfate comprises a concentration in a range from about 0.150 moles per liter to about 0.200 moles per liter, and ranges therebetween, the cobalt sulfate comprises a concentration in a range from about 0.01 moles per liter to 0.04 moles per liter, and ranges therebetween, and the ferric ammonium sulfate comprises a concentration in a range from about 0.005 moles per liter to about 0.040 moles per liter.

3. The method of claim 1 , wherein a temperature of the aqueous electroless plating bath is in a range from about 25° C. to about 45° C., and ranges therebetween.

4. The method of claim 1 , wherein the cobalt-iron-boron alloy comprises an amorphous or a nano-crystalline microstructure.

Assignees

• IBM

Inventors

• Deligianni Hariklia
• Gallagher William J
• Luo Yu
• Romankiw Lubomyr T
• Yoon Joonah

Classifications

• C23C18/50 Primary

  with alloys based on iron, cobalt or nickel · CPC title

• H01F41/24

  from liquids · CPC title

• H01F41/046

  structurally combined with ferromagnetic material · CPC title

• H01F10/30

  characterised by the composition of the intermediate layers {, e.g. seed, buffer, template, diffusion preventing, cap layers (H01F10/06 and H01F10/32 take precedence)} · CPC title

• H01F10/16

  containing cobalt ({H01F10/126} , H01F10/13 take precedence) · CPC title