Browse Prior Art Database

Method for the in-place preparation of CNTs in a nanopaste matrix

IP.com Disclosure Number: IPCOM000100606D
Publication Date: 2005-Mar-15
Document File: 4 page(s) / 93K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for the in-place preparation of carbon nanotubes (CNTs) in a nanopaste matrix. Benefits include improved functionality and improved performance.

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 54% of the total text.

Method for the in-place preparation of CNTs in a nanopaste matrix

Disclosed is a method for the in-place preparation of carbon nanotubes (CNTs) in a nanopaste matrix. Benefits include improved functionality and improved performance.

Background

      Microelectronic device packages are rapidly progressing towards thinner profiles, particularly for mobile applications, such as personal digital assistants and laptop computers. To enhance the reliability of the fragile inner layer dielectrics (ILDs), the substrate must be closely matched to the coefficient of thermal expansion (CTE) of the device. As a result, ceramic is being considered as a potential option for substrates. However, for equivalent performance, ceramic substrates are thicker compared to their organic counterparts. In many ultra-miniaturized applications, no space is available to provide a conventional thermal solution above the device using heatsink. The packaging industry must provide thermal solutions via the interconnect side of the flip-chip device.

      Conventionally, no real viable solution exists. A possibility is to provide thermal vias in the package. However, the existing material sets do not have the thermal conductivity to handle the expected increase in the heat removal requirement.

      Conventionally, the thermal solution is provided on the top side of the device using a heat spreader and a heatsink (see Figure 1). For low-profile applications, alternatives being actively pursued include using thermal vias that would transmit heat from the controlled collapse chip collect (C4) joint to the land side of the package. With ceramic substrates, holes can be punched or laser drilled or mechanically drilled. The holes are then coated with Cu and filled with solder or other thermal solution material that has a heat conductivity of < 100 W/mK. However, these materials cannot meet the expected requirements.

General description

      The disclosed method is in-place preparation of CNTs in a nanopaste matrix. This material is used for filling thermal vias in low-profile applications where ceramic substrate is used.

              CNTs have much higher thermal conductivity of most conventional materials used for filling thermal via holes.

              A displacement reaction occurs to form the interface between the Cu hole wall and the paste.

              The key elements of the method include:

•             In-place formation of CNTs by carbonization in thermal vias

•             Formation of a nanopaste matrix for the CNTs using nanoparticles

Advantages

              The disclosed method provides advantages, including:

•             Improved functionality due to enabling much finer via holes be...