Air-biased probe for semiconductor device bonding

Claim 2

A self-aligning method of automatically transferring integrally leaded semiconductor device chips to a conductive lead frame and for automatically consistently producing uniform low stress bonds therebetween, said method comprising: inserting a semiconductive device chip into each of a plurality of spaced recesses in an upper surface of a carrier template, each of said chips having a face with a plurality of soft ferromagnetic integral leads thereon, with each of said chip faces being oriented upwardly; supporting on said template upper surface a conductive lead frame having a plurality of soft ferromagnetic finger sets in register over corresponding template recesses, with said fingers corresponding to said integral chip leads; raising said chips on soft ferromagnetic supports into close proximity with the underside of their overlying finger sets; magnetically raising said chips up off their supports into engagement with their overlying finger sets and precisely aligning them therewith; re-engaging the backside of the chips with their respective supports without further significantly elevating said chips and overstressing said lead frame fingers; flowing a hot gas onto said finger sets and said chips while said chips are in re-engagement with their respective supports to bond said integral chip leads to their corresponding lead frame fingers without disturbing said precise alignment therebetween; terminating said flow of hot gas; and withdrawing the supports from said chips.

Claim 3

A self-aligning method of automatically transferring integrally leaded semiconductor device chips to a conductive lead frame and for automatically consistently producing uniform low stress bonds therebetween, said method comprising: placing a semiconductor device chip having a face with a plurality of soft ferromagnetic integral leads thereon into each of adjacent recesses in an upper surface of a carrier template so that said chip faces are oriented upwardly, said template recesses having openings extending to a lower surface of the template; supporting on said template upper surface a conductive lead frame having sets of a plurality of soft ferromagnetic fingers corresponding to said integral chip leads wherein a finger set oVerlies each chip in the template recesses; forcing an air pressure into a chamber to bias a plurality of soft ferromagnetic probes slidably mounted therein and extending vertically therefrom, said probes being spaced apart equivalent to the distance between the openings of adjacent template recesses; applying a magnetic force to the probes so that magnetic lines of flux flow longitudinally therethrough; extending the probes through the openings of adjacent template recesses to engage the backside of the chips therein; raising the chips closer to the overlying lead frame fingers until the magnetic force transmitted through the probe precisely aligns the integral chip leads with their corresponding fingers and further raises the chips up from the probes to the fingers to produce engagement between all of the integral chip leads of each chip and their corresponding lead frame fingers; re-engaging the backside of the chips with the probes to hold the chips in register with their corresponding lead frame finger sets, said probes being partially regressed into said chamber so as not to upwardly bend the lead frame fingers upon re-engagement; and heating said integral chip leads and said fingers in engagement therewith with a blast of hot gas to simultaneously bond the chips to their respective lead frame finger sets without disturbing said precisely aligned engagement therebetween.

Claim 4

A self-aligning method of automatically transferring integrally leaded semiconductor device chips to a conductive lead frame and for automatically consistently producing uniform low stress bonds therebetween, said method comprising: placing a semiconductor device chip having a face with a plurality of soft ferromagnetic integral leads thereon into each of adjacent recesses in an upper surface of a carrier template so that said chip faces are oriented upwardly, said template recesses having openings extending to a lower surface of the template; supporting on said template upper surface a conductive lead frame having sets of a plurality of soft ferromagnetic fingers corresponding to said integral chip leads wherein a finger set oVerlies each chip in the template recesses; forcing an air pressure into a chamber to bias a plurality of soft ferromagnetic probes slidably mounted therein and extending vertically therefrom, said probes being spaced apart equivalent to the distance between the openings of adjacent template recesses; applying a magnetic force to the probes so that magnetic lines of flux flow longitudinally therethrough; extending the probes through the openings of adjacent template recesses to engage the backside of the chips therein; raising the chips closer to the overlying lead frame fingers until the magnetic force transmitted through the probe precisely aligns the integral chip leads with their corresponding fingers and further raises the chips up from the probes to the fingers to produce engagement between all of the integral chip leads of each chip and their corresponding lead frame fingers; re-engaging the backside of the chips with the probes to hold the chips in register with their corresponding lead frame finger sets, said probes being partially regressed into said chamber so as not to upwardly bend the lead frame fingers upon re-engagement; and heating said integral chip leads and said fingers in engagement therewith with a blast of hot gas to simultaneously bond the chips to their respective lead frame finger sets without disturbing said precisely aligned engagement therebetween.

Claim 5

Apparatus for automatically consistently producing uniform low stress bonds between integrally leaded semiconductor device chips and a conductive lead frame, said apparatus comprising: a temporary semiconductor device carrying template having a plurality of spaced recesses in an upper surface thereof, said template recesses having openings extending to an opposite surface of the template; means for supporting on said one template surface a conductive lead frame having a plurality of spaced finger sets so that each of said finger sets overlies a template recess, said finger sets having a plurality of spaced mutually convergent soft ferromagnetic fingers corresponding to integral leads on a semiconductor device chip; a transfer apparatus having a soft ferromagnetic vertically extending member, means for applying a magnetic force to said member, means for successively vertically raising said member and magnetic means, and means on one end of said member for receiving a probe holding apparatus; a probe holding apparatus for mounting onto said member receiving means, said probe holding apparatus having a soft ferromagnetic housing defining a cylinder, a cavity in the cylinder, an orifice extending vertically from the cavity to the periphery of the housing, a soft ferromagnetic probe slidably mounted in the orifice and extending therefrom, and an opening extending from the periphery of the housing into the cavity for introducing a differential air pressure therein; an air pressure source connected to said opening for forcing an air pressure into the cavity to vertically bias said probe, said probe being so biased that it is capable of carrying a semiconductor device chip in a template recess into close proximity with its overlying lead frame finger sets so that the magnetic force can automatically orient and transfer it from the probe into engagement with the fingers, but so that the probe will partially regress into the cavity so as to not bend the fingers after re-engaging the backside of the chip to hold it in register with the fingers; and means for flowing a hot gas onto said chip-finger engagement while the backside of the chip is re-engaged with said probe without disturbing the precise integral chip lead-finger registration.

Claim 6

Apparatus for automatically consistently producing uniform low stress bonds between integrally leaded semiconductor device chips and a conductive lead frame, said apparatus comprising: a temporary semiconductor device carrying template having a plurality of spaced recesses in an upper surface thereof, said template recesses having openings extending to an opposite surface of the template; means for supporting on said one template surface a conductive lead frame having a plurality of spaced finger sets so that each of said finger sets overlies a template recess, said finger sets having a plurality of spaced mutually convergent soft ferromagnetic fingers corresponding to integral leads on a semiconductor device chip; a transfer apparatus having a soft ferromagnetic vertically extending member, means for applying a magnetic force to said member, means for successively vertically raising said member and magnetic means, and means on one end of said member for receiving a probe holding apparatus; a probe holding apparatus for mounting onto said member receiving means, said probe holding apparatus having a soft ferromagnetic housing defining a cylinder, a cavity in the cylinder, an orifice extending vertically from the cavity to the periphery of the housing, a soft ferromagnetic probe slidably mounted in the orifice and extending therefrom, and an opening extending from the periphery of the housing into the cavity for introducing a differential air pressure therein; an air pressure source connected to said opening for forcing an air pressure into the cavity to vertically bias said probe, said probe being so biased that it is capable of carrying a semiconductor device chip in a template recess into close proximity with its overlying lead frame finger sets so that the magnetic force can automatically orient and transfer it from the probe into engagement with the fingers, but so that the probe will partially regress into the cavity so as to not bend the fingers after re-engaging the backside of the chip to hold it in register with the fingers; and means for flowing a hot gas onto said chip-finger engagement while the backside of the chip is re-engaged with said probe without disturbing the precise integral chip lead-finger registration.

Claim 7

The apparatus of claim 3 which includes means on said probe for deflecting air escaping from said orifice.