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Chip Removal/Replacement Process

IP.com Disclosure Number: IPCOM000080819D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

McNutt, RD: AUTHOR

Abstract

This is a microflame process for removing and replacing chips on a ceramic substrate having nickel-plated lands for interconnection. A battery of infrared lamps bias heat the substrate, the heat of these lamps being controlled by an infrared detector focused on the chip being worked. The detector sends a signal to a controller that controls the lamp output. The dressing chip and replacement chip are prefluxed and baked to permit easier handling and precise control over the amount of flux used. The gas fed to the microflame is throttled by a closed system using an infrared detector, proportional controller and leak valve that is motorized. This system controls the resulting temperature of the chip during processing.

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Chip Removal/Replacement Process

This is a microflame process for removing and replacing chips on a ceramic substrate having nickel-plated lands for interconnection. A battery of infrared lamps bias heat the substrate, the heat of these lamps being controlled by an infrared detector focused on the chip being worked. The detector sends a signal to a controller that controls the lamp output. The dressing chip and replacement chip are prefluxed and baked to permit easier handling and precise control over the amount of flux used. The gas fed to the microflame is throttled by a closed system using an infrared detector, proportional controller and leak valve that is motorized. This system controls the resulting temperature of the chip during processing. The dressing chip process utilizes a silicon-type chip, but substitutes a chrome-copper metallurgy in place of the usual metallurgy. General.

The substrate is heated from below by a battery of infrared lamps. These lamps are controlled by a proportional controller that is regulated by an infrared detector, focused on the chip being reworked.

The chip is heated by a gas fed flame made up of oxygen-hydrogen and methyl alcohol. The flame is directed at the center of the back of the chip. The temperature of the chip is controlled by regulating the amount of gas being burned at the flame nozzle. A proportional controller operates a needle valve in the gas supply system. This controller is regulated by the signals produced by the infrared detector focused on the chip.

Set point devices operating off of the infrared detector, initiate steps in the process as specified temperatures are reached. A timer regulates the duration of the process once the chip reaches its peak temperature. Chip Removal.

The substrate is heated from below by an infrared heater. When the chip surface temperature reaches 215 degrees C, the microflame is ignited. The chip temperature rises rapidly toward 350 degrees C. When 340 degrees C is reached in about 3 seconds, the timer that controls the length of the process is started. The chip temperature is maintained at 350 degrees C. At the end of the timed cycle of 3 seconds, the vacuum is turned on lifting the chip. The microflame is blown...