High temperature eutectic solder ball attach

• US 6,824,041 B2
• Filed: 10/21/2002
• Issued: 11/30/2004
• Est. Priority Date: 10/21/2002
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Grieder, Andrew, Lazar, Alexander
• Primary Examiner(s): Stoner, Kiley S.
• Application Number:
  US10/274,749
• Publication Number:
  US 20040074950A1
• Time in Patent Office: 771 Days
• Field of Search: 228/180.22, 228/245, 228/246, 257/737, 257/738, 438/613
• US Class Current: 228/180.22
• CPC Class Codes: B23K 1/0016 Brazing of electronic components
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: H01L 2224/81 using a bump connector
• CPC Class Codes: H05K 2201/094 Array of pads or lands differing from one another, e.g. in size, pitch or thickness; Using different connections on the pads
• 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 3/3463 Solder compositions in relation to features of the printed circuit board or the mounting process
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

High melt balls dispersed on the surface of a ball grid array package in such a manner that the collapse of eutectic solder balls is controlled during reflow heating in order to ensure appropriate solder ball standoff, pitch and coplanarity of the ball grid array package from the substrate or printed circuit board surface to which it is being attached.

Claims

1. A ball grid array package, comprising:

an array of eutectic solder balls on a surface of the ball grid array package; and

at least one high melt ball on the same surface of the BGA package, wherein said at least one high melt ball has pre-flow diameter of approximately 15-20 mils.

2. The ball grid array package in accordance with claim 1, wherein said at least one high melt ball is at least one high melt ball in each corner of said surface of said ball grid array package.

4. The ball grid array package in accordance with claim 1, wherein said at least one high melt ball comprises approximately 90% lead and 10% tin.

5. The ball grid array package in accordance with claim 1, wherein said at least one high melt ball has a melting point high enough that it does not reflow during a normal reflow heating process to reflow the eutectic solder balls.

3. A ball grid array package, comprising:

an array of eutectic solder balls on a surface of the ball grid array package; and

at least one high melt ball on a surface of the BGA package, wherein said eutectic solder balls comprise approximately, 62% tin, 2% silver, and 36% lead.

6. A hail grid array package comprising:

an array of eutectic solder balls on a surface of the ball grid array package; and

at least one high melt ball on the same surface of the BGA package, wherein said eutectic solder balls have a pre-reflow diameter of approximately 20-25 mils and a post-reflow standoff of approximately 15-20 mils.

7. A ball grid array package comprising:

an array of eutectic solder ball on the ball grid array package; and

at least one high melt on the same surface of the BGA package, wherein said eutectic solder balls have a post-reflow standoff of approximately 15-20 mils.

8. The ball grid array package in accordance with claim 7, wherein said at least one high melt ball has a pre-reflow diameter of approximately 20 mils.

9. An electronic assembly having a first surface, said electronic assembly comprising:

an array of eutectic solder balls arranged on said first surface;

at least one high melt ball on said first surface of said electronic assembly, wherein in array of eutectic solder balls have post-reflow standoff of approximately 20-25 mils.

10. An electronic assembly comprising an electronic component having a first surface attached to a first surface of a substrate, wherein the first surface of the electronic component is attached to the first surface of the substrate according to the following steps:

forming an array of eutectic solder balls across the first surface of the electronic component;

forming more than one high melt ball with a predetermined diameter on the first surface of the electronic component;

bringing the eutectic solder balls into contact with the first surface of the substrate; and

heating the eutectic solder balls without melting the high melt balls, such that the eutectic solder balls compress to the standoff of the diameter of the high melt balls, wherein said array of eutectic solder balls have a post-reflow standoff of approximately 20-25 mils.