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Method for copper bumps for second-level interconnection

IP.com Disclosure Number: IPCOM000144752D
Publication Date: 2007-Jan-06
Document File: 2 page(s) / 17K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for copper bumps for second-level interconnection. Benefits include improved functionality, improved performance, improved reliability, and improved ease of implementation.

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Method for copper bumps for second-level interconnection

Disclosed is a method for copper bumps for second-level interconnection. Benefits include improved functionality, improved performance, improved reliability, and improved ease of implementation.

Background

      An environmental requirement for the semiconductor industry is the creation of lead-free solutions, especially for mobile and handheld devices. The conventional bump metallurgy and surface finishing solutions for second-level interconnections are not very robust during shock conditions.

      Another requirement is finer ball-grid array (BGA) bump pitch to meet product functionality requirements. However, no clear solutions exist for meeting these requirements.

      The conventional solution for bump metallurgy is tin-silver-copper (Sn-Ag-Cu) solder for second-level interconnections on the package side. Electroless nickel immersion gold is used for under-bump metallization (UBM).

      The short-term solutions for shock-condition robustness include adding sacrificial BGA joints and corner glues.

      First-level interconnections conventionally use copper bumps as a lead-free process.

Description

      The disclosed method is electroplated copper bumps for second-level interconnections. The method uses titanium (Ti) as UBM for bump-to-copper-pad bonding (see Figure 1).

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