Method and apparatus for electroless plating a contact pad

• US 6,346,151 B1
• Filed: 12/16/1999
• Issued: 02/12/2002
• Est. Priority Date: 02/24/1999
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Jiang, Tongbi, Li, Li
• Primary Examiner(s): BARR, MICHAEL E
• Application Number:
  US09/465,541
• Time in Patent Office: 789 Days
• Field of Search: 118/403, 118/429, 134/902, 134/84
• US Class Current: 118/403
• CPC Class Codes: H01L 21/02052 Wet cleaning only H01L21/02085 takes precedence
• CPC Class Codes: H01L 21/288 from a liquid, e.g. electrolytic deposition
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76828 thermal treatment
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213
• CPC Class Codes: H01L 21/7685 the layer covering a conductive structure H01L21/76849 takes precedence
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/131 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 24/03 Manufacturing methods
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01011 Sodium [Na]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 Silicon [Si]
• CPC Class Codes: H01L 2924/01016 Sulfur [S]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01075 Rhenium [Re]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/05042 : Si3N4
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/19043 : being a resistor
• CPC Class Codes: Y10S 134/902 : Semiconductor wafer

Abstract

A method and apparatus is disclosed for sequential processing of integrated circuits, particularly for conductively passivating a contact pad with a material which resists formation of resistive oxides. In particular, a tank is divided into three compartments, each holding a different solution: a lower compartment and two upper compartments divided by a barrier, which extends across and partway down the tank. The solutions have different densities and therefore separate into different layers. In the illustrated embodiment, integrated circuits with patterned contact pads are passed through one of the upper compartments, in which oxide is removed from the contact pads. Continuing downward into the lower compartment and laterally beneath the barrier, a protective layer is selectively formed on the insulating layer surrounding the contact pads. As the integrated circuits are moved upwardly into the second upper compartment, a conducting monomer selectively forms on the contact pads prior to any exposure to air. The integrated circuits can then be transferred to an ozone chamber where polymerization results in a conductive passivation layer on the contact pad.

Claims

1. A sequential, liquid phase treatment apparatus, comprising:

a tank having a lower compartment, an upper first compartment, and an upper second compartment adjacent to and separated from the upper first compartment by a barrier, wherein the lower compartment extends beneath and is open to the upper first compartment and the upper second compartment;

a cleaning solution held in the upper first compartment;

a siliconizing solution held in the lower compartment; and

a plating solution held in the upper second compartment.

2. The apparatus of claim 1, wherein the cleaning solution comprises an oxide etchant.

3. The apparatus of claim 1, wherein the siliconizing solution comprises dichloro-octamethyl-tetrasiloxane.

4. The apparatus of claim 1, wherein the plating solution comprises a conducting monomer, the apparatus further comprising an ozone chamber.

5. The apparatus of claim 1, wherein the tank comprises sidewalls formed of polytetrafluoroethylene.

6. An apparatus for sequential in situ cleaning and formation of a conductive passivation layer on a conductive element in an integrated circuit, the apparatus comprising:

a tank;

a first liquid treatment phase within the tank, comprising an aqueous cleaning solution having a first density;

a second liquid treatment phase within the tank, the second phase having a second density different from the first density, the second phase being immiscible and in direct contact with the first phase, the second phase is more dense than and extending under the first phase; and

a third liquid treatment phase having a third density different from the second density, the third phase being immiscible with the second phase and in direct contact therewith.

7. The apparatus of claim 6, wherein the second phase selectively forms a protective layer over an insulating layer surrounding the conductive element and the third phase selectively forms a conducting material over the conductive element.

8. The apparatus of claim 7, wherein the conductive element comprises a bond pad for connecting the integrated circuit to an outside circuit.

9. The apparatus of claim 6, wherein the second phase comprises an organic solvent.