Browse Prior Art Database

Heat Sink for Semiconductor Device Chips

IP.com Disclosure Number: IPCOM000074890D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Oktay, S: AUTHOR [+2]

Abstract

In this method for producing a brush-like exchanging structure on a semiconductor device ship, an electroless plating bath is provided in which a given amount of ferromagnetic powder is distributed uniformly. Completed semiconductor wafers are placed at the bottom of the bath, the rear wafer surfaces facing upward. An array of poles of a singly electromagnet is placed immediately below each wafer, each pole registering with a respective chip position on the wafer. Upon applying current to each electromagnet, substantially equal amounts of ferromagnetic powder are attracted towards each magnet pole. This results in the erection of brush-like structures of ferromagnetic particles on the rear surfaces of the wafers.

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Heat Sink for Semiconductor Device Chips

In this method for producing a brush-like exchanging structure on a semiconductor device ship, an electroless plating bath is provided in which a given amount of ferromagnetic powder is distributed uniformly. Completed semiconductor wafers are placed at the bottom of the bath, the rear wafer surfaces facing upward. An array of poles of a singly electromagnet is placed immediately below each wafer, each pole registering with a respective chip position on the wafer. Upon applying current to each electromagnet, substantially equal amounts of ferromagnetic powder are attracted towards each magnet pole. This results in the erection of brush-like structures of ferromagnetic particles on the rear surfaces of the wafers. By raising the bath temperature to the required operating temperature for electroless plating, while each electromagnet remains energized, a uniform deposit of electroless metal transforms the brushlike structures into rigid heat exchangers. By this process a heat sink is obtained which is firmly attached to each wafer at the chip locations, so that the diced wafers yield individual chips each having their own heat exchanging structure.

The use of this brush-like heat exchanging structure allows an efficient and continuous bubble nucleation by applying direct immersion cooling during the operation of the chips. This causes the coolant to boil at lower temperatures and over a wide temperature range than are achieve...