Browse Prior Art Database

Detecting BGA Package Overheating and Re-Balling

IP.com Disclosure Number: IPCOM000028050D
Publication Date: 2004-Apr-21
Document File: 3 page(s) / 475K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses a hybrid "sacrificial" solder ball (i.e. one that is not used for I/O or power delivery) to detect BGA package overheating and solder re-balling.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Detecting BGA Package Overheating and Re-Balling

Disclosed is a method that uses a hybrid “sacrificial” solder ball (i.e. one that is not used for I/O or power delivery) to detect BGA package overheating and solder re-balling.

Background

Electronic components are sensitive to high temperatures during the solder reflow process in motherboard manufacturing. Specifically, FC-BGA packages cannot exceed three reflow cycles (of greater than 183oC) and a maximum reflow temperature of 225oC. If this occurs, the FC-BGA package first-level interconnect degrades significantly and can cause premature failures in a computer system. Additionally, the substrate of the package can delaminate if overheated or exposed to more than three reflow cycles. These failures are well known; however, a detection device for the FC-BGA component does not exist for this out-of-specification condition. This makes it difficult or impossible for failure analysis to detect the overheating, making Intel liable for out-of-specification conditions at the board manufacturing factory.

General Description

The disclosed method detects any out-of-specification package processing at customer board assembly specifically due to overheating or re-balling. The disclosed method uses the concept of different liquid diffusion patterns (see Figure 1). Homogenous lead diffusion occurs at temperatures exceeding the solder ball melting temperature (i.e. liquid-to-liquid diffusion), while grain boundary diffusion occurs at temperature below the solder ball melting temperature
(i.e. liquid-to-solid diffusion).

As in the current leaded BGA package, all solder balls on the package are SnPb eutectic, with a melting temperature of 183oC. To detect overheating or re-balling, a package with a hybrid ball (with a melting temperature of ToC) is used. An implementation o...