Lead free alloy bump structure and fabrication method

• US 7,994,043 B1
• Filed: 04/24/2008
• Issued: 08/09/2011
• Est. Priority Date: 04/24/2008
• Status: Active Grant

• Current Assignee: Amkor Technology Singapore Holding Pte., Ltd. (Amkor Technology Incorporated)
• Original Assignee: Amkor Technology Incorporated
• Inventors: Rinne, Glenn A., Mis, J. Daniel
• Primary Examiner(s): Pham; Thanh V
• Assistant Examiner(s): HENRY, CALEB E
• Application Number:
  US12/108,909
• Time in Patent Office: 1,202 Days
• Field of Search: 438/612, 438/613
• US Class Current: 438/612
• CPC Class Codes: H01L 2224/0345 Physical vapour deposition [PVD], e.g. evaporation, or sputtering
• CPC Class Codes: H01L 2224/03462 Electroplating
• CPC Class Codes: H01L 2224/03472 Profile of the lift-off mask
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/05027 the internal layer extending out of an opening
• CPC Class Codes: H01L 2224/05099 Material
• CPC Class Codes: H01L 2224/05124 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/05147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05166 Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/05186 with a principal constituent of the material being a non metallic, non metalloid inorganic material
• CPC Class Codes: H01L 2224/05552 in top view
• CPC Class Codes: H01L 2224/05564 Only on the bonding interface of the bonding area
• CPC Class Codes: H01L 2224/05572 the external layer extending out of an opening
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/05655 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/1145 Physical vapour deposition [PVD], e.g. evaporation, or sputtering
• CPC Class Codes: H01L 2224/1146 Plating
• CPC Class Codes: H01L 2224/1147 using a lift-off mask
• CPC Class Codes: H01L 2224/11472 Profile of the lift-off mask
• CPC Class Codes: H01L 2224/11502 Pre-existing or pre-deposited material
• CPC Class Codes: H01L 2224/11849 : Reflowing
• CPC Class Codes: H01L 2224/119 : Methods of manufacturing bump connectors involving a specific sequence of method steps
• CPC Class Codes: H01L 2224/11901 : with repetition of the same manufacturing step
• CPC Class Codes: H01L 2224/13082 : Two-layer arrangements
• CPC Class Codes: H01L 2224/13083 : Three-layer arrangements
• CPC Class Codes: H01L 2224/13099 : Material
• 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 2224/13111 : Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/13139 : Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/13147 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/13599 : Material
• CPC Class Codes: H01L 2224/29099 : Material
• CPC Class Codes: H01L 2224/29599 : Material
• CPC Class Codes: H01L 24/11 : Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 24/13 : of an individual bump connector
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00013 : Fully indexed content
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01024 : Chromium [Cr]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/04941 : TiN
• CPC Class Codes: H01L 2924/14 : Integrated circuits

Abstract

A method includes forming a patterned resist layer comprising a resist layer opening overlying a bond pad of a substrate. The resist layer opening is at least partially filled with a first solder component layer. A second solder component layer is formed on the first solder component layer. The patterned resist layer is removed. The first solder component layer and the second solder component layer are reflowed to form a lead free binary metal alloy solder bump electrically connected to the bond pad.

Claims

1. A method comprising:

forming a patterned resist layer on a substrate comprising a bond pad, the patterned resist layer comprising a resist layer opening overlying the bond pad;

completely filling the resist layer opening with a first solder component layer, the first solder component layer comprising a first planar surface substantially coplanar with a principal surface of the patterned resist layer;

forming a second solder component layer on the first planar surface of the first solder component layer that is substantially coplanar with the principal surface of the patterned resist layer and on the entire principal surface of the patterned resist layer;

removing the patterned resist layer and any portion of the second solder component layer on the principal surface of the patterned resist layer; and

reflowing the first solder component layer and the second solder component layer to form a binary metal alloy solder bump electrically connected to the bond pad.

2. The method of claim 1 wherein the first solder component layer is formed by plating.

3. The method of claim 2 wherein the first solder component layer is formed by electroplating.

4. The method of claim 1 wherein the second solder component layer is formed using a deposition selected from the group consisting of evaporation, sputtering, electroplating, or electroless.

5. The method of claim 1 wherein the first solder component layer comprises tin.

6. The method of claim 5 wherein the second solder component layer comprises silver.

7. The method of claim 6 wherein the binary metal alloy solder bump comprises a binary tin-silver alloy solder.

8. The method of claim 5 wherein the second solder component layer comprises copper, and wherein the binary metal alloy solder bump comprises a binary tin-copper alloy solder.

9. The method of claim 1 further comprising

forming a primary barrier layer on the substrate;

forming a conductor layer on the primary barrier layer;

forming a secondary barrier layer in the resist layer opening and on the conductor layer; and

selectively removing the conductor layer using the secondary barrier layer as a mask.

10. The method of claim 9 further comprising selectively removing the primary barrier layer using the secondary barrier layer as a mask.

11. The method of claim 1 wherein the patterned resist layer has a profile selected from the group consisting of sloped, vertical and retrograde.