Apparatus for cleaning of circuit substrates
View Patent ↗Silicon wafers and the like are cleaned using new scrubber-type apparatus in which measures are taken to compensate for differential cleaning of the central region of the wafer by: using rotary brushes having one or more non-contact portions arranged in the section thereof that faces the central region of the substrate, or toggling the relative position of the wafer and the rotary brushes, or directing cleaning fluid(s) preferentially towards the central region of the wafer. Another aspect of the invention provides scrubber-type cleaning apparatus in which the rotary brushes are replaced by rollers ( 110 ). A web of cleaning material ( 116 ) is interposed between each roller and the substrate. Various different webs of cleaning material may be used, e.g. a length of tissue, a continuous loop of cleaning material whose surface is reconditioned on each cleaning pass, adhesive material provided on a carrier tape, etc.
1. A circuit substrate cleaning apparatus comprising:
a pair of elongate rollers arranged such that curved surfaces thereof oppose each other across a gap, each roller being rotatable about its longitudinal axis and the outer curved surface of each roller being adapted for cleaning; and
circuit substrate support means for supporting and rotating a circuit substrate between, and in contact with, the rollers, the circuit substrate support comprising at least four pair of capstans, each capstan of each pair of capstans being movable between a first position in contact with the edge of the circuit substrate and a second position spaced apart from each other by a distance sufficient to pass around the pair of elongated rollers, at least two pairs of capstans of the plurality of pairs of capstans concurrently in contact with the circuit substrate when the pair of elongated rollers is in contact with the circuit substrate;
characterized by comprising compensating means adapted to reduce inequalities in cleaning across a radial direction of the circuit substrate; wherein the compensating means comprises means for moving the circuit substrate relative to the rollers in the radial direction of the circuit substrate while the circuit substrate is being supported and rotated between the rollers.
2. Circuit substrate cleaning apparatus according to claim 1 , wherein the compensating means comprises one or more non-contact regions provided in the curved surfaces of the rollers at a location arranged to face said central region of a circuit substrate being supported between the rollers.
3. Circuit substrate cleaning apparatus according to claim 1 , wherein the compensating means comprises means for directing cleaning fluid towards said central region of the circuit substrate while the circuit substrate is being supported and rotated between the rollers.
4. Circuit substrate cleaning apparatus comprising:
a pair of elongate rollers arranged such that curved surfaces thereof oppose each other across a gap, each roller being rotatable about its longitudinal axis;
circuit substrate support means for supporting a circuit substrate in the gap between the rollers; and
feeding means for feeding a web of cleaning material between one of said rollers and a circuit substrate supported in the gap between the rollers such that, in use, the cleaning material contacts said circuit substrate;
wherein the support means is configured to reduce inequalities in cleaning across the radial direction of the circuit substrate;
wherein:
the rollers are wider than the circuit substrate to be cleaned; and
the circuit substrate support means comprises a plurality of pairs of capstans, the capstans of each pair being movable between a first position in contact with the edge of the circuit substrate and a second position spaced apart from each other by a distance sufficient to pass around the rollers, at least two pairs of capstans of the plurality of pairs of capstans concurrently in contact with the circuit substrate when the web of cleaning material is in contact with the circuit substrate;
wherein the plurality of pairs of capstans or the rollers are configured to move the circuit substrate in a radial direction of the circuit substrate relative to the rollers to reduce inequalities in cleaning across the radial direction of the circuit substrate.
5. Circuit substrate cleaning apparatus according to claim 4 , and further comprising dispensing means for applying cleaning fluid to at least one of said web of cleaning material and said circuit substrate.
6. Circuit substrate cleaning apparatus according to claim 4 , wherein the feeding means is arranged to feed between a roller and a circuit substrate supported in the gap between the rollers a web of cleaning material comprising a layer of porous material and an impermeable backing tape, with the backing tape arranged to face towards the roller.
7. Circuit substrate cleaning apparatus according to claim 4 , wherein the feeding means is arranged to feed between a roller and a circuit substrate supported in the gap between the rollers a web of cleaning material comprising a layer of adhesive material and a carrier tape, with the carrier tape arranged to face towards the roller.
8. Circuit substrate cleaning apparatus according to claim 4 , wherein the feeding means comprises means for feeding a first web of cleaning material between a first one of said rollers and a first major surface of a circuit substrate supported in the gap between the rollers and means for feeding a second web of cleaning material between the second one of said rollers and the second major surface of said circuit substrate.
9. Circuit substrate cleaning apparatus according to claim 4 , and comprising a surface-reconditioning station for reconditioning the surface of said web of cleaning material, wherein the feeding means is adapted to circulate a continuous loop of cleaning material along a path passing through the gap between the rollers and passing through the surface-reconditioning station.
10. Circuit substrate cleaning apparatus according to claim 9 , and comprising a rinsing station for rinsing said web of cleaning material, wherein the feeding means is adapted to circulate the continuous loop of cleaning material along a path passing through said rinsing station.
11. Circuit substrate cleaning apparatus according to claim 4 , wherein the circuit substrate support means is arranged such that the capstans impart a rotary motion to the circuit substrate being cleaned.
12. Circuit substrate cleaning apparatus according to claim 4 , wherein said plurality of pairs of capstans comprises a first set of capstans adapted to contact the circuit substrate before the circuit substrate has made contact with the web of cleaning material and a second set of capstans adapted to contact the circuit substrate after the circuit substrate has made contact with the web of cleaning material.
13. Circuit substrate cleaning apparatus according to claim 4 , wherein at least one pair of capstans of the at least two capstans is in contact with the circuit substrate on one side of the center line of the circuit substrate and at least one other pair of capstans of the at least two capstans with the circuit substrate on the other side of the center line of the circuit substrate when the web of cleaning material is in contact with the circuit substrate.
14. Circuit substrate cleaning apparatus according to claim 4 , wherein the rollers translate relative to the circuit substrate and the plurality of pairs of capstans.