Browse Prior Art Database

Method for solder-well immersed chip attachment

IP.com Disclosure Number: IPCOM000033145D
Publication Date: 2004-Nov-29
Document File: 2 page(s) / 67K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for solder-well immersed chip attachment. Benefits include improved functionality, improved reliability, and improved ease of implementation.

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 56% of the total text.

Method for solder-well immersed chip attachment

Disclosed is a method for solder-well immersed chip attachment. Benefits include improved functionality, improved reliability, and improved ease of implementation.

Background

      The conventional high-temperature chip joint process induces stress on solder joints, resulting in low-k dielectric failures and joint fatigue. The contact area is uncontrolled, which is a function of the wicking action, bump alignment, and bump wetting. The maximum current draw (Imax) deteriorates due to void formation caused by the high-density electron flow.

      Conventionally, the bump size is increasing, which increases the contact area. However, this trend is limited by requirements for smaller bump pitches.

General description

              The disclosed method is a chip-attach process where Cu bumps are immersed in a low melting point solder well.

              The key elements of the method include:

•             Solder well to contain solder

•             Low melting point solder

•             Lower chip joint temperature

•             Lower yield strength solder

Advantages

              The disclosed method provides advantages, including:

•             Improved functionality due to enabling fails to be recovered by annealing above the solder melting temperature, which is below the normal board processing temperatures

•             Improved reliability due to reducing the stress on the joints and preventing joint failure

      not requiring additional processing steps

•             Improved ease of implementation due to being implemented with the conventional tool set used for the chip-attach process

Detailed description

      The disclosed method produces a solder-well immersed chip joint (see Figures 1 and...