US 4,160,893 AGranted

Individual chip joining machine

AssigneeInternational Business Machines Corporation

InventorsRobert H. Meyen, Karl J. Puttlitz, Karl Schink, Herbert Wenskus

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Abstract

An individual chip joining machine is designed primarily to bond a single chip to a multi-chip substrate. The machine includes an X-Y table for moving a substrate to locate a chip site beneath a probe. The probe serves to pick up a chip and either place it on the substrate or remove it therefrom and further serves to heat the chip to join it to the substrate by solder reflow or to melt the solder and allow the chip to be removed. The probe is mounted on a Z direction placement mechanism that also includes means to allow the probe to be backed off a fixed distance from a chip, once the chip has been placed on the substrate preparatory to joining thereto. A second heater heats the substrate to a bias temperature, this heating being controlled through use of a surrogate substrate having a thermocouple attached thereto.

Claims14

Dependent claims

In soldering apparatus for multichip modules each having a substrate provided with a plurality of chip sites on one face thereof, and wherein the elevation of each chip site within a module may vary and the thickness of different substrates may vary, a combined chip handling and heating tool comprising:

a selectively energizable infrared radiant heat source,
a reflector surrounding said heat source and having a first opening therein,
a quartz plate covering said first opening,
and a shield covering said plate and having a second opening therein thru which said radiant energy passes, said reflector being operative to direct radiant energy through said plate and said first and second openings and concentrate such energy in a focal plane over an area of substantially the same size as a chip, said plane being external to said tool and located a fixed distance therefrom;
said shield being operative to limit said radiant energy to only the chip being worked on by said tool, said shield having a conical tip extending from said plate and terminating in an edge surrounding said second opening, said edge being adapted to engage a chip;
first means adapted to selectively connect said tool to a vacuum source for selectively holding a chip against said edge;
said tip and plate defining a chamber communicating with said first means whereby the lower pressure is said chamber due to connection to the vacuum source allows a chip to be held against said edge due to atmospheric pressure;
and second means for producing relative movement between said tool and a chip site to locate a chip thereon and to locate said tool so that solder on the chip is in said focal plane of said radiant energy.

5 more elements

In soldering apparatus joining a flat chip having solder balls on one face thereof to a preselected chip site of a substrate populated with other chips, said chip site including pads to be joined to the solder balls, the combination comprising:

a probe comprising
a selectively energizable infrared source,
reflector means operative to concentrate infrared energy from said source into a focal plane located beneath said probe,
a shield substantially opaque to the passage of energy from said source having an opening therein through which radiant energy passes, said opening being of approximately the same size as that of the pattern of balls on the chip, said opening being above the focal plane,
and first means to selectively connect said probe to a vacuum source allowing a chip to be supported by said probe in a position covering said opening;
second means adapted to support a substrate beneath said probe with a chip site thereon vertically aligned with the chip supported by said probe;
and third means operative to support said probe above said second means and move said probe vertically between an upper position spaced above said substrate, a lower position engaged with a chip on the chip site and a heating position located between said upper and lower positions, the solder on a chip on a chip site being in said focal plane when said probe is in said heating position, said third means comprising:
a first plate movable vertically between raised and lowered positions a distance greater than the distance between said upper and lower positions of said probe,
fourth means for selectively moving said first plate between said raised and lowered positions,
a second plate connected to said probe,
fifth means floatingly mounting said second plate on said first plate for movement therewith as said first plate moves from said raised position towards said lowered position until said probe reaches said lower position and for relative movement as said probe remains in said lower position while said first slide moves into said lowered position, said fifth means being operative to allow movement of said probe from said lower position to said heating position while said first slide is in said lowered position,
and sixth means for moving said second slide relative to said first slide to move said probe from said lower position to said heating position.

9 more elements

Dependencies are inferred from the claim text.