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Method for coaxial solder ball shielding to reduce signal transmission loss between a component and a board

IP.com Disclosure Number: IPCOM000011941D
Publication Date: 2003-Mar-26
Document File: 4 page(s) / 148K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for coaxial solder ball shielding to reduce signal transmission loss between a component and a board. Benefits include improved performance.

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Method for coaxial solder ball shielding to reduce signal transmission loss between a component and a board

Disclosed is a method for coaxial solder ball shielding to reduce signal transmission loss between a component and a board. Benefits include improved performance.

Background

              As telecommunication and wireless devices go to higher frequencies and transmission speeds, the design of interconnect structures between the component and the board must be optimized (see Figure 1). The component/board solder ball/ pins, which conventionally are short enough to be treated as a lump element, are electrically long enough to be modeled as distributed transmission lines. The conventional technology has a high input/output (I/O) impedance mismatch and high inductance power delivery (PD), resulting in signal transmission loss and higher droop. For example, at 40 GHz, a 1-mm ball pitch solder ball can have a height of 410 µm, which is large (wavelength/10, assuming dielectric constant of 4). The issue is greater for pin-type devices where the length is multiple of the solder ball.

General description

              The disclosed method uses coaxial solder ball shielding to reduce signal loss between the component and board. Honeycomb ground sheets are used to provide shielding between solder balls. This method reduces the impedance of input/output and power delivery inductance between component/board.

Advantages

              The disclosed method provides advantages, including:

•             Improved performance due to an improved inductance path for power delivery

•             Improved performance du...