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Method for a microprocessor package with lossy polymer gel-filled IHS cavity and lossy polymer dam around a silicon die

IP.com Disclosure Number: IPCOM000008972D
Publication Date: 2002-Jul-26
Document File: 6 page(s) / 132K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a microprocessor package with lossy polymer gel-filled IHS cavity and lossy polymer dam around a silicon die. Benefits include improved signal quality and improved thermal performance.

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Method for a microprocessor package with lossy polymer gel-filled IHS cavity and lossy polymer dam around a silicon die

Disclosed is a method for a microprocessor package with lossy polymer gel-filled IHS cavity and lossy polymer dam around a silicon die. Benefits include improved signal quality and improved thermal performance.

Background

              As the performance of microprocessors increase, silicon transistor switching occurs more frequently. High processor frequency requires EMI suppression in the multi-GHz range, which increasingly constrains the system-level (inside a computer chassis) EMI containment. As a result, requirements exist for more EMI gasket materials for the sheet metal seam, which impacts cost. Requirements also exist for a smaller wave-guide feature size, which could have a potential thermal performance impact due to limited air flow. Therefore, the effectively reduction or elimination of EMI attenuation at its source is essential.

              For example, EMI and attenuation occur on a conventional desktop system with a microprocessor PGA package and integrated heat spreader (IHS, see Figure 1). Because the integrated heatsink is not connected to the electrical ground, the EMI attenuation from the die penetrates the IHS and extends inside the computer chassis. Constraint is added to system-level EMI management. ESD travels from the outside to the inside of the package. All computer systems must pass mandatory EMI/ESD testing.

              Microprocessor packages without IHSs are used in mobile platforms and PGA package for socket connections. Because there is no enclosed cover to confine the EMI wave, it spreads from the silicon die to the inside of the computer chassis, adding constraints to system-level EMI management (see Figure 2). ESD travels from the outside to the inside of the package and could cause electrical signal interference or even damage to the package circuitry.

Description

              The disclosed method is to fill inside the IHS cavity of a desktop processor package with an EMI/ESD lossy polymer gel material, such as:

·        Silicone

·        Acrylic

·        Urethane

               One or more materials are added, such as:

·        Ferrite

·        Iron

·        Carbon

·        Other filler additives

              The lossy polymer gel material is injected into the package cavity with an additional air-venting hole on the lid of IHS This design avoids air entrapment inside the cavity and provide good fill all way around the inside the cavity. The gel material can start out as liquid fluid before gelling occurs, so it can be easily injected or dis...