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Chemical Cleaning Technique for Vibratory Bowl Feeder

IP.com Disclosure Number: IPCOM000045881D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Frank, V: AUTHOR

Abstract

Vibratory feed bowls are employed to orient flip chip type semiconductor chips for pick-up and placement onto tester stations or onto module substrates. The tin-lead solder balls projecting on one side of the flip chip engage spiral grooves on the surface of the vibratory feed bowl. The bowl is driven into a vibratory mode, thereby causing the chips to migrate along the spiral grooves to a point at which they are selectively oriented and picked up for subsequent placement. While the chips move along the respective grooves of the bowl, the tin-lead composition of the solder balls rubs off onto the surface of the grooves in the bowl, thereby contaminating the grooves and impeding the motion of the chips.

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Chemical Cleaning Technique for Vibratory Bowl Feeder

Vibratory feed bowls are employed to orient flip chip type semiconductor chips for pick-up and placement onto tester stations or onto module substrates. The tin-lead solder balls projecting on one side of the flip chip engage spiral grooves on the surface of the vibratory feed bowl. The bowl is driven into a vibratory mode, thereby causing the chips to migrate along the spiral grooves to a point at which they are selectively oriented and picked up for subsequent placement. While the chips move along the respective grooves of the bowl, the tin-lead composition of the solder balls rubs off onto the surface of the grooves in the bowl, thereby contaminating the grooves and impeding the motion of the chips.

Previously, these vibratory bowls would be withdrawn from service and cleaned by directing onto their surface a vapor blast having a composition of water and powdered pumice. This quasi-sandblasting operation has the drawback of abrading the nickel-plated surface of the bowl so that the life of the bowl is limited to a finite number of cleaning operations. In addition, after a vapor blasting cleaning operation, the spiral grooves are left with unusually sharp edges which are not suitable for the chip-feeding operation. Therefore, after the existing vapor blast cleaning operations, the vibratory bowls must be "broken in" by operating them with dummy chips for a period of time so that an initial quantity of tin lead solder is deposited on the spiral grooves to dull them and make them more suitable for chip feeding.

The following cleaning technique has been substi...