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Method for a drop-in heatsink/heat slug with a well mold for MMAP LDI technology

IP.com Disclosure Number: IPCOM000012199D
Publication Date: 2003-Apr-16
Document File: 6 page(s) / 119K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a drop-in heatsink/heat slug with a well mold for molded matrix array package (MMAP) low-density interconnect (LDI) technology. Benefits include improved thermal performance.

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Method for a drop-in heatsink/heat slug with a well mold for MMAP LDI technology

Disclosed is a method for a drop-in heatsink/heat slug with a well mold for molded matrix array package (MMAP) low-density interconnect (LDI) technology. Benefits include improved thermal performance.

Background

              Heat dissipates from microprocessors in molded packages. The temperature loss must be controlled to meet die junction-temperature (Tj) targets. Historically, heat removal has been a concern for central processor unit (CPU) products only. The demand for more complexity and functionality from LDI non-CPU products increases their power consumption. The power level for these devices is increasing rapidly, and heat removal is becoming critical for this market segment as well. Standard non-CPU processors are molded using nonconductive molding compounds. These molding materials resist the heat generated by the internal die by dissipating out to the ambient environment, potentially creating reliability issues.

              CPU products with higher power conventionally use heat dissipation technologies. An integrated heat spreader directs the heat from the die. Then, a heatsink dissipates the heat to the ambient environment. This package-level solution for heat removal adds significant cost to the total package cost and is prohibitive for the low-cost non-CPU market.

              A direct die-referencing solution exposes the backside of the die and connects it to the heatsink, using a thermal interface material (TIM) such as grease or phase-change material.

              For MMAP non-CPU packages, a conventional solution is to have a lower/limited power delivered to the package.

              MMAP type molding is critical in the LDI non-CPU market segment for meeting low cost targets and high units per hour (UPH) targets. Molding compounds are required to mechanically seal the packages and provide good reliability performance.

              Conventional molding uses a flat mold compound surface with a flat heat slug (see Figure 1).

              A conventional well mold design is produced by injection molding where a plunger introduces the mold material into a reservoir. The package is overmolded (see Figure 2).

General description

              The disclosed method is a drop-in heatsink/heat slug with a well mold for molded matrix array package (MMAP) low-density interconnect (LDI) technology. The disclosed method is applicable to molded LDI packages where heat transfer from the die through the molding compound is critical.

              The key elements of the method include:

•             Drop-in heatsink or heat slug that is a generic heatsink or heat slug design with a protrusion of some area of the heatsink/heat slug base

•             Well mold design with some portion of the molding surface removed at the center of the die

Advantages

              The disclosed method provides advantages, including:

•             Improved thermal performance due to the lessening of the heat-path resist...