Ball grid array interface structure and method

• US 20070045845A1
• Filed: 08/31/2005
• Published: 03/01/2007
• Est. Priority Date: 08/31/2005
• Status: Abandoned Application

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Shah, Dhaval, Lal, Anand
• Application Number:
  US11/216,961
• Publication Number:
  US 20070045845A1
• Time in Patent Office: Days
• US Class Current: 257/738
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• 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 24/02 Bonding areas on insulating substrates, e.g. chip carriers, H01L23/49816, H01L23/49838, H01L23/5389; Manufacturing methods related thereto
• CPC Class Codes: H01L 24/10 Bump connectors bumps on insulating substrates, e.g. chip carriers, H01L23/49816; Manufacturing methods related thereto
• 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 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01082 Lead [Pb]
• CPC Class Codes: H01L 2924/01327 Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H05K 1/111 Pads for surface mounting, e.g. lay-out
• CPC Class Codes: H05K 2201/0367 Metallic bump or raised conductor not used as solder bump solder materials or compositions and methods of application thereof H05K3/3457
• CPC Class Codes: H05K 2201/0373 Conductors having a fine structure, e.g. providing a plurality of contact points with a structured tool providing micro- or nanometer scale roughness on a metal surface H05K2203/0307
• CPC Class Codes: H05K 3/3436 : having an array of bottom contacts, e.g. pad grid array or ball grid array components
• CPC Class Codes: H05K 3/3457 : Solder materials or compositions; Methods of application thereof
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

A structure and method (1000) of forming an interface for a ball grid array includes forming pad (204), (1002) on a substrate (202) and creating a positive feature (206) on the pad (1004). The positive feature (206) provides an interface for a solder ball (208). The improved pad can be incorporated as part of BGA substrate or as part of a printed circuit board substrate. The positive feature (206) provides a contoured or uneven profile having vertical surfaces that increase the pad'"'"'s surface area without taking up additional substrate space. The vertical surface area interrupts propagation of any fracture incurred during drop and vibration.

Claims

1. An interface assembly for a ball grid array, comprising:

a substrate;

a pad coupled to the substrate; and

a positive feature formed on the pad, the pad and positive feature for adhering to a solder ball.

2. The interface assembly of claim 1, wherein the substrate comprises a ball grid array (BGA) substrate.

3. The interface assembly of claim 1, wherein the substrate comprises a printed circuit board.

4. The interface assembly of claim 1, wherein the positive feature provides an increased surface area to the pad without additional substrate space.

5. The interface assembly of claim 1, wherein the positive feature of the pad includes a vertical surface for breaking a propagation of a fracture along the interface.

6. The interface assembly of claim 1, wherein the positive feature of the pad includes an inclined surface for breaking a propagation of a fracture along the interface.

7. A surface mount component, comprising:

a ball grid array (BGA) substrate;

a pad coupled to the BGA substrate; and

at least one positive feature created on the pad;

a solder ball bumped onto the pad and positive feature.

8. The surface mount component of claim 7, wherein the at least one positive feature increases the pad'"'"'s surface area without taking up additional BGA substrate space.

9. The surface mount component of claim 7, wherein the at least one positive feature of the pad includes a vertical surface.

10. The surface mount component of claim 7, wherein the at least one positive feature of the pad includes an inclined surface.

11. The surface mount component of claim 7, wherein the at least one positive feature of the pad includes a non-flat profile.

12. The surface mount component of claim 7, wherein the at least one positive feature minimizes a propagation of a fracture along an interface between the solder ball and the BGA substrate.

13. A method of forming an interface for a ball grid array, comprising the steps of:

providing a substrate;

forming pad on the substrate;

creating a positive feature on the pad, the positive feature providing an interface for a solder ball.

14. The method of claim 13, wherein the substrate comprises a ball grid array (BGA) substrate.

15. The method of claim 14, further comprising the step of bumping the pads of the BGA substrate with solder balls.

16. The method of claim 13, wherein the substrate comprises a printed circuit board.

17. The method of claim 13, wherein the positive feature interrupts prorogation of a fracture along an interface between the solder ball and substrate.