Use of palladium in IC manufacturing with conductive polymer bump

• US 6,939,744 B2
• Filed: 05/05/2003
• Issued: 09/06/2005
• Est. Priority Date: 05/21/1996
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Farnworth, Warren M., Akram, Salman
• Primary Examiner(s): Whitehead, Jr., Carl
• Assistant Examiner(s): Hogans, David L.
• Application Number:
  US10/430,616
• Publication Number:
  US 20030199160A1
• Time in Patent Office: 855 Days
• Field of Search: 438/108, 438/612, 438/613, 438/614, 438/686, 438615-617, 438/604, 438/106, 257/737, 257/778, 257/750
• US Class Current: 438/119
• CPC Class Codes: H01L 21/288 from a liquid, e.g. electrolytic deposition
• CPC Class Codes: H01L 21/4853 Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 2224/05001 Internal layers
• CPC Class Codes: H01L 2224/05022 the internal layer being at least partially embedded in the surface
• CPC Class Codes: H01L 2224/05023 the whole internal layer protruding from the surface
• CPC Class Codes: H01L 2224/05164 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05571 the external layer being disposed in a recess of the surface
• 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 2224/11 Manufacturing methods
• CPC Class Codes: H01L 2224/1132 Screen printing, i.e. using a stencil
• CPC Class Codes: H01L 2224/12 Structure, shape, material or disposition of the bump connectors prior to the connecting process
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/13111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/1319 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/29099 Material
• CPC Class Codes: H01L 2224/29101 : the principal constituent melting at a temperature of less than 400°C
• CPC Class Codes: H01L 2224/29111 : Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/2919 : with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/29199 : Material of the matrix
• CPC Class Codes: H01L 2224/2929 : with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/29298 : Fillers
• CPC Class Codes: H01L 2224/29299 : Base material
• CPC Class Codes: H01L 2224/73203 : Bump and layer connectors
• CPC Class Codes: H01L 2224/73204 : the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/81801 : Soldering or alloying
• CPC Class Codes: H01L 2224/8319 : Arrangement of the layer connectors prior to mounting
• CPC Class Codes: H01L 2224/838 : Bonding techniques
• CPC Class Codes: H01L 23/49811 : Additional leads joined to the metallisation on the insulating substrate, e.g. pins, bumps, wires, flat leads H01L23/49827 takes precedence
• CPC Class Codes: H01L 23/49816 : Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
• CPC Class Codes: H01L 23/49894 : Materials of the insulating layers or coatings
• 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 24/12 : Structure, shape, material or disposition of the bump connectors prior to the connecting process
• CPC Class Codes: H01L 24/16 : of an individual bump connector
• CPC Class Codes: H01L 24/29 : of an individual layer connector
• CPC Class Codes: H01L 24/81 : using a bump connector
• CPC Class Codes: H01L 24/83 : using a layer 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 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00013 : 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/0132 : Binary Alloys
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/0665 : Epoxy resin
• CPC Class Codes: H01L 2924/0781 : being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/12044 : OLED
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/3512 : Cracking
• CPC Class Codes: H05K 2201/10674 : Flip chip
• CPC Class Codes: H05K 2201/10977 : Encapsulated connections applying non-metallic protective coatings for encapsulating mounted components H05K3/284
• CPC Class Codes: H05K 2201/10984 : Component carrying a connection agent, e.g. solder, adhesive soldering leadless components having an array of bottom contacts H05K3/3436; BGA components H05K2201/10734
• CPC Class Codes: H05K 3/244 : Finish plating of conductors, especially of copper conductors, e.g. for pads or lands selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3457, e.g. by plating H05K3/3473
• CPC Class Codes: H05K 3/321 : by conductive adhesives

Abstract

An apparatus and a method for forming a substrate having a palladium metal layer over at least one contact point of the substrate and having a flexible conductive polymer bump, preferably a two-stage epoxy, on the palladium plated contact point, are provided. The present invention also relates to assemblies comprising one or more of these substrates.

Claims

1. A method of forming a conductive bump on a first substrate having a conductive electrode and having a first thermal coefficient of expansion for connection of said first substrate to a conductive electrode of a second substrate having a second thermal coefficient of expansion, comprising:

applying at least one layer of palladium on a portion of said conductive electrode of either or both substrates; and

disposing a two-stage conductive polymer bump on a portion of said at least one palladium layer, said two-stage conductive polymer bump for substantially eliminating mismatch between said first thermal coefficient of expansion of said first substrate and said second thermal coefficient of expansion of said second substrate.

2. The method of claim 1, further comprising:

applying a passivation layer over a portion of a surface of either or both substrates having said conductive electrode.

3. The method of claim 2, further comprising:

etching a portion of said passivation layer to expose a portion of said conductive electrode.

4. The method of claim 1, wherein disposing a two-stage conductive polymer bump comprises disposing a two-stage epoxy bump on a portion of said at least one palladium layer.

5. The method of claim 1, wherein applying said at least one layer of palladium on a portion of said conductive electrode of said either or both substrates comprises:

immersing said either or both substrates in an electroless plating solution containing palladium dispersed therein.

6. The method of claim 1, wherein disposing a two-stage conductive polymer bump on a portion of said at least one palladium layer comprises applying a layer of a polymer with a silk screen to form said two-stage conductive polymer bump.

7. The method of claim 1, wherein disposing a two-stage conductive polymer bump on a portion of said at least one palladium layer comprises applying multiple layers of a polymer with a silk screen to form said two-stage conductive polymer bump.

8. The method of claim 1, wherein said either or both substrates having said conductive electrode comprises a silicon wafer having at least one conductive electrode.

9. The method of claim 1, wherein said either or both substrates having said conductive electrode comprises providing a printed circuit board having at least one said conductive electrode.

10. The method of claim 1, wherein said either or both substrates having a conductive electrode comprises a semiconductor die having at least one bond pad.

11. The method of claim 1, wherein disposing a two-stage conductive polymer bump comprises disposing a two-stage conductive polymer bump including palladium therein on a portion of said at least one palladium layer.