Strength of Micro-Bump Joints

• US 20150037936A1
• Filed: 10/22/2014
• Published: 02/05/2015
• Est. Priority Date: 05/28/2010
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Shen, Wen-Wei, Chen, Chen-Shien, Kuo, Chen-Cheng, Chen, Ming-Fa, Wang, Rung-De
• Granted Patent: US 9,219,046 B2
• Time in Patent Office: Days
• US Class Current: 438/106
• CPC Class Codes: H01L 2224/03614 by chemical means only
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/05017 comprising protrusions or indentations
• CPC Class Codes: H01L 2224/05023 the whole internal layer protruding from the surface
• CPC Class Codes: H01L 2224/05124 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/05139 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/05147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05155 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/05552 in top view
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05572 the external layer extending out of an opening
• CPC Class Codes: H01L 2224/05647 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05666 Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/1146 Plating
• CPC Class Codes: H01L 2224/11823 Immersion coating, e.g. in a solder bath
• CPC Class Codes: H01L 2224/11831 involving a chemical process, e.g. etching the bump connector
• CPC Class Codes: H01L 2224/1191 Forming a passivation layer after forming the bump connector
• CPC Class Codes: H01L 2224/13005 Structure
• CPC Class Codes: H01L 2224/13017 being non uniform along the bump connector
• CPC Class Codes: H01L 2224/13018 comprising protrusions or indentations
• CPC Class Codes: H01L 2224/13019 : at the bonding interface of the bump connector, i.e. on the surface of the bump connector
• CPC Class Codes: H01L 2224/13076 : being mutually engaged together, e.g. through inserts
• CPC Class Codes: H01L 2224/1308 : being stacked
• CPC Class Codes: H01L 2224/13083 : Three-layer arrangements
• CPC Class Codes: H01L 2224/13111 : Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/13124 : Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/13139 : Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/13144 : Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/13147 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/13155 : Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/13164 : Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/13565 : Only outside the bonding interface of the bump connector
• CPC Class Codes: H01L 2224/1357 : Single coating layer
• CPC Class Codes: H01L 2224/1369 : with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/16145 : the bodies being stacked
• CPC Class Codes: H01L 2224/16148 : the bump connector connecting to a bonding area protruding from the surface
• CPC Class Codes: H01L 2224/16238 : the bump connector connecting to a bonding area protruding from the surface of the item
• CPC Class Codes: H01L 2224/81193 : wherein the bump connectors are disposed on both the semiconductor or solid-state body and another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/81345 : Shape, e.g. interlocking features
• CPC Class Codes: H01L 2224/81801 : Soldering or alloying
• CPC Class Codes: H01L 2224/81815 : Reflow soldering
• CPC Class Codes: H01L 2225/06513 : Bump or bump-like direct electrical connections between devices, e.g. flip-chip connection, solder bumps
• CPC Class Codes: H01L 2225/06541 : Conductive via connections through the device, e.g. vertical interconnects, through silicon via [TSV]
• CPC Class Codes: H01L 23/3157 : Partial encapsulation or coating mask layer used as insulation layer H01L21/31
• CPC Class Codes: H01L 24/03 : Manufacturing methods
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• 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 24/16 : of an individual bump connector
• CPC Class Codes: H01L 24/81 : using a bump connector
• CPC Class Codes: H01L 25/0657 : Stacked arrangements of devices
• CPC Class Codes: H01L 25/50 : Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• 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 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• 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 2924/05042 : Si3N4
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/206 : Length ranges
• CPC Class Codes: H01L 2924/35 : Mechanical effects
• CPC Class Codes: Y10T 428/12361 : having aperture or cut
• CPC Class Codes: Y10T 428/12396 : Discontinuous surface component

Abstract

A device includes a work piece including a metal bump; and a dielectric layer having a portion directly over the metal bump. The metal bump and a surface of the portion of the dielectric layer form an interface. A metal finish is formed over and contacting the metal bump. The metal finish extends from over the dielectric layer to below the interface.

Claims

1. A method of forming a device, the method comprising:

forming a metal bump on a first work piece;

forming a dielectric layer over and contacting the metal bump;

forming an opening in the dielectric layer to expose a portion of the metal bump;

etching the portion of the metal bump exposed through the opening to form a recess, a portion of the recess extending to directly under the dielectric layer; and

forming a metal finish on the metal bump, with at least a portion of the metal finish formed in the recess.

2. The method of claim 1 further comprising providing a second work piece comprising an additional metal bump, and bonding the additional metal bump of the second work piece to the metal bump of the first work piece.

3. The method of claim 1, wherein the step of etching the portion of the metal bump is performed using the dielectric layer as a self-aligned mask, with no additional mask formed over the dielectric layer.

4. The method of claim 1 further comprising:

after the step of forming the opening, forming a patterned mask over the dielectric layer, the metal bump comprising portions exposed through the patterned mask; and

performing the step of etching the portion of the metal bump through openings in the patterned mask.

5. The method of claim 1, wherein the recess comprises a plurality of isolated portions isolated from each other by un-etched portions of the metal bump.

6. The method of claim 1, wherein the step of etching comprises an isotropic etching process.

7. The method of claim 1, wherein the step of forming the metal finish comprises electroless plating.

8. The method of claim 1, wherein the metal bump comprises copper, and wherein the metal finish comprises nickel.

9. A method of forming a device, the method comprising:

forming a metal bump protruding above a top surface of a substrate, the metal bump comprising sidewalls and a top surface;

forming a dielectric layer comprising a first portion directly over the top surface of the metal bump, and a second portion on the sidewalls of the metal bump, the metal bump and the first portion of the dielectric layer forming an interface;

etching the first portion of the dielectric layer to form an opening, a portion of the metal bump being exposed through the opening;

etching the portion of the metal bump to form a recess in the metal bump, the recess extending to directly under the dielectric layer to form an undercut; and

performing a selective plating to form a metal finish in the recess, a portion of the metal finish extending into the undercut.

10. The method of claim 9, wherein the metal finish comprises a portion extending to directly over the first portion of the dielectric layer.

11. The method of claim 9, wherein the recess comprises a plurality of isolated portions isolated from each other by un-etched portions of the metal bump.

12. The method of claim 9, wherein the step of etching the portion of the metal bump is performed with no additional mask formed over the dielectric layer.

13. The method of claim 9, wherein the step of etching the portion of the metal bump is performed with a patterned mask over the dielectric layer, and wherein the portion of the metal bump is etched through openings in the patterned mask.

14. The method of claim 9, wherein the metal finish comprises electroless nickel electroless palladium immersion gold (ENEPIG).

15. A method of forming a device, the method comprising:

forming a metal bump on a first work piece, the metal bump comprising a top surface comprising a center portion and an edge portion surrounding the center portion;

forming a dielectric layer to cover the edge portion of the metal bump;

recessing the center portion of the metal bump to form a recess in the metal bump; and

plating a metal finish on the metal bump, the metal finish comprising a portion extending down into the recess and directly under a portion of the dielectric layer.

16. The method of claim 15 further comprising providing a second work piece comprising an additional metal bump, and bonding the additional metal bump of the second work piece to the metal finish.

17. The method of claim 15, wherein the metal finish comprises another portion extending to directly over the dielectric layer.

18. The method of claim 15, wherein the step of etching the center portion of the metal bump is performed using the dielectric layer as a self-aligned mask.

19. The method of claim 15 further comprising:

forming a patterned mask over the metal bump, a portion of the metal bump being exposed through the patterned mask; and

performing the step of recessing through the patterned mask.

20. The method of claim 15, wherein the metal bump comprises copper.