Browse Prior Art Database

Method for CNTs in trenches on a die backside for cooling hotspots

IP.com Disclosure Number: IPCOM000101594D
Publication Date: 2005-Mar-16
Document File: 4 page(s) / 41K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for carbon nanotubes (CNTs) in trenches on a die backside for cooling hotspots. Benefits include improved functionality, improved thermal performance, 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 55% of the total text.

Method for CNTs in trenches on a die backside for cooling hotspots

Disclosed is a method for carbon nanotubes (CNTs) in trenches on a die backside for cooling hotspots. Benefits include improved functionality, improved thermal performance, and improved performance.

Background

              A major impediment to the future performance of microprocessors is the requirement to remove heat from circuits, particularly at hot spots. The conventional copper IHS must be replaced with a thinner, highly thermal conductivity material.

              Most silicon chips develop hotspots on the die with temperatures much higher than the average. These hotspots are difficult to cool with current cooling technologies, such as using a heatsink, because the cooling solution is far from the transistors (~800 µm).

              Conventional cooling solutions have a thin layer of an adhesive material between the silicon die and a heat spreader/heatsink. TIM material is sandwiched between the die and the IHS. This layer is designated as TIM 1. Another TIM layer is sandwiched between the IHS and the heatsink. This layer is designated as TIM 2. The capability to reduce qjc and the CTE mismatch between the die and IHS is important for package performance and reliability (see Figure 1).

General description

              The disclosed method creates CNTs in trenches formed locally in the backside of a die for cooling hot-spot regions. A cover layer is added to protect the CNTs and provide thermal contact. Embedding the CNTs in the silicon forms a low-thermal-impedance path to the die backside. Using the CNTs only in a local region, eliminates the requirement for thinning the wafer, which maintains its mechanical strength.

      The key elements of the method include:

•             Forming deep trenches within a local region on the backside of the die

•             Depositing a seed layer

•             Growing CNTs in the trenches

•             Using a cover layer to protect and make thermal contact with the CNTs

•             Local cooling of hot spots on the die

Advantages

              The disclosed method provides advantages, including:

•             Improved functionality due to providing hotspot cooling by creating CNTs in trenches formed locally in the backside of a die without the use of TIM

•             Improved thermal performance due to removing heat at hotspots using CNTs

•             Improved performance due to forming a low-thermal-impedance path to the die backside by embedding CNTs in the silicon

•             Impro...