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Protective Cap for Ibm Module During Rework

IP.com Disclosure Number: IPCOM000039149D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Diedrick, DL: AUTHOR [+3]

Abstract

An arrangement is described which allows Pin In Hole (PIN) module epoxy/cap interface temperatures to stay under the 275oF limit during the rework of an adjacent surface-mounted component (SMC) with hot air. A major concern in Surface Mount Technology is the detrimental effect hot air rework of SMCs has on the reliability of adjacent modules. The extreme heat (400-500oF) from rework has the potential to cause a separation between the metal cap and the epoxy inside the cap of the modules. This separation is a long term reliability concern. Contamination in the separation could eventually corrode and cause the module to fail. Many methods have been tried to solve this problem. The collet (nozzle attached to the hot air machine, used to direct the flow of hot air) has been modified, but still can't block the thermal excursion.

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Protective Cap for Ibm Module During Rework

An arrangement is described which allows Pin In Hole (PIN) module epoxy/cap interface temperatures to stay under the 275oF limit during the rework of an adjacent surface-mounted component (SMC) with hot air. A major concern in Surface Mount Technology is the detrimental effect hot air rework of SMCs has on the reliability of adjacent modules. The extreme heat (400-500oF) from rework has the potential to cause a separation between the metal cap and the epoxy inside the cap of the modules. This separation is a long term reliability concern. Contamination in the separation could eventually corrode and cause the module to fail. Many methods have been tried to solve this problem. The collet (nozzle attached to the hot air machine, used to direct the flow of hot air) has been modified, but still can't block the thermal excursion. Other rework machines (e.g., hotbar rework machines) control where the heat goes, but cannot be used for all types of Surface Mounted Components. Other materials (phenolic and crystallized volcanic rock) were made into caps to protect the module from heat, but didn't prevent the interface from becoming hotter than is allowable. In accordance with the new arrangement, the module (when it is adjacent to a SMC that requires rework) is covered with a cap made from an insulative, wool-like material that withstands rework temperatures. "Kaowool Blanket"* is an example of the type of material that, when use...