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Method for a high thermal-capacity wafer chuck

IP.com Disclosure Number: IPCOM000029163D
Publication Date: 2004-Jun-16
Document File: 7 page(s) / 150K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a high thermal-capacity wafer chuck. Benefits include improved functionality, improved performance, and improved yield.

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Method for a high thermal-capacity wafer chuck

Disclosed is a method for a high thermal-capacity wafer chuck. Benefits include improved functionality, improved performance, and improved yield.

Background

      High-capacity heat transfer is required for integrated circuits in an unsingulated wafer.

      Conventionally, chucks make physical contact with a wafer. Heat is transferred without the use of an interface fluid through the area where mechanical contact is made between the chuck and wafer (see Figure 1, item 2). The actual contact surface is not continuous due to micro-topography mismatches between the chuck and wafer backside surfaces. This mismatch reduces the effectiveness of the heat transfer in regions where contact is not made (marked as 1.3) because heat is not efficiently transferred by air/gasses.

      Conventional thermal chuck technologies are intended for the electrical testing of individual units. The thermal requirements for burn-in are higher due to the use of higher power to accelerate fallout and reduce process time. Wafer level burn-in on multiple units further increases the thermal solution demands.

General description

      The disclosed method is a fixture that provides high capacity thermal dissipation for wafer level applications.

              The key elements of the method include:

•             Thermal interface fluid as a primary or as an intermediate heat transfer medium

•             Formation of an air/liquid tight seal between the chuck and wafer

Advantages

              The disclosed method provides advantages, including:

•             Improved functionality due to enabling thermal control for wafer-level burn-in of high power products

•             Improved performance due to increasing the surface/thermal interface contact area between the wafer and the transfer medium

•             Improved performance due to increasing the heat transfer capability for wafer heating and/or cooling

•             Improved yield due to reducing the number of rejected units

Detailed description

      The disclosed method uses a thermal interface fluid (TIF) (2.13) to transfer heat between an active heatsink (2.17) and the wafer. The active heatsink can be temperature controlled by methods such as but not limited to liquid cooling, thermal electric coolers, vapor chambers, and forced air cooling (see Figure 2). The TIF is intended to create a thin interface layer between the wafer and the active heatsink, but the thickness can be varied as required (see Figures 3 and...