Apparatus and method using rotational indexing for laser marking IC packages carried in trays

• US 6,528,760 B1
• Filed: 07/14/2000
• Issued: 03/04/2003
• Est. Priority Date: 07/14/2000
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Canella, Robert L., Ibarra, Tony T.
• Primary Examiner(s): Evans, Geoffrey S.
• Application Number:
  US09/617,517
• Time in Patent Office: 963 Days
• Field of Search: 219/121.68, 219/121.69, 219/121.82, 414/795.3, 414/788.7, 414/797.5, 414/798.1
• US Class Current: 219/121.82
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 26/042 Automatically aligning the laser beam
• CPC Class Codes: B23K 26/0838 by using an endless conveyor belt
• CPC Class Codes: H01L 21/67282 Marking devices

Abstract

An apparatus for laser marking IC packages carried in trays includes a transport actuator extending from an input shuttle assembly to an output shuttle assembly. The laser marking apparatus further includes a tray transport movable on the transport actuator and configured to receive a cooperatively configured tray carrier. The input shuttle assembly is adapted to load a tray carrying unmarked IC packages onto the tray carrier from a stack of trays on the input shuttle assembly. A tray bearing unmarked IC packages may travel on the tray carrier borne by the tray transport to a laser marking station positioned above the transport actuator and having a single laser marking head traversing one mark field disposed within an enclosure. A first portion of the IC packages disposed in the tray that are positioned in the mark field may be laser marked after the tray is lifted into the enclosure by a rotational lift mechanism located proximate the laser marking station.

Claims

1. An apparatus for laser marking IC packages carried in trays, comprising:

a laser marking station;

a tray handling device configured to transport trays bearing IC packages to a location proximate said laser marking station for laser marking; and

a rotational indexing mechanism disposed adjacent said laser marking station configured to rotate a tray bearing IC packages positioned at said location about an axis transverse to a plane of said tray.

2. The apparatus of claim 1, wherein said rotational indexing mechanism is further configured to position said tray bearing IC packages positioned at said location at a laser focal length for laser marking.

3. A laser marking apparatus for laser marking IC packages carried in trays, each of said trays configured to support a generally planar array of IC packages, said apparatus comprising:

a laser marking head having a mark field;

a tray handling device configured to supply a tray bearing an array of IC packages to said laser marking head and to position a first portion of said array of IC packages in said mark field for laser marking; and

a rotational indexing mechanism disposed proximate said laser marking head configured to rotate said tray bearing an array of IC packages to position a second portion of said array of IC packages in said mark field for laser marking.

4. The apparatus of claim 3, wherein said rotational indexing mechanism is further configured to move said tray bearing an array of IC packages to position said IC packages at a laser focal length for laser marking.

5. The apparatus of claim 3, wherein said tray handling device comprises:

a transport device defining a generally horizontal tray path having a first end and an opposing second end, a portion of said tray path between said first end and said second end positioned adjacent said laser marking head;

a tray input device disposed at said first end of said tray path configured to supply trays bearing an array of IC packages to said transport device for marking, said tray input device having a keying structure configured to supply said trays in a keyed orientation; and

a tray output device disposed at said second end of said tray path configured to receive trays bearing an array of IC packages from said transport device after marking, said tray output device having a keying structure configured to receive said trays in a keyed orientation.

6. The apparatus of claim 5, wherein said keyed orientation of said tray input device is opposite said keyed orientation of said tray output device.

7. The apparatus of claim 3, wherein:

said first portion of said array of IC packages comprises one half of said array of IC packages and said second portion of said array of IC packages comprises another half of said array of IC packages; and

said rotational indexing mechanism is further configured to rotate said tray bearing an array of IC packages 180 degrees to effect said positioning of said second portion of said array of IC packages in said mark field for laser marking.

8. A system for marking IC packages carried in trays, comprising:

a transport actuator defining a horizontal path;

a tray transport secured to said transport actuator and movable thereon along said horizontal path;

a tray carrier carried by, and unsecured to, said tray transport for receiving trays of IC packages;

an input shuttle assembly for providing trays of IC packages to said tray carrier;

an output shuttle assembly for receiving trays of IC packages from said tray carrier;

a laser marking station disposed adjacent a portion of said transport actuator between said input shuttle assembly and said output shuttle assembly; and

a rotational lift mechanism disposed proximate said laser marking station configured to lift said tray carrier off said tray transport and to rotate said tray carrier.

9. The system of claim 8, wherein said rotational lift mechanism comprises:

a vertical lift mechanism configured for extension and retraction in a vertical direction relative to said horizontal path of said transport actuator;

a rotary actuator assembly secured to said vertical lift mechanism; and

a tray manipulator secured to said rotary actuator assembly configured to engage said tray carrier.

10. The system of claim 9, wherein said vertical lift mechanism comprises:

a horizontally movable drive wedge element having an inclined upper surface;

a dual-action drive mechanism configured to horizontally move said drive wedge element;

a dual-action stop mechanism configured and located to selectively limit travel of said drive wedge element;

a vertically movable slave wedge element having an inclined lower surface of like angle of inclination to said inclined upper surface of said drive wedge element, said slave wedge element having said rotary actuator assembly secured thereto; and

at least one linear bearing configured to horizontally constrain said slave wedge element and said rotary actuator assembly, permitting movement of said slave wedge element and said rotary actuator assembly substantially only in said vertical direction.

11. The system of claim 10, wherein said dual-action drive mechanism comprises a pneumatically actuated drive block to which said drive wedge element is mounted, said drive block being slidable on at least one guide shaft.

12. The system of claim 10, wherein said dual-action stop mechanism comprises a dual-action air cylinder adjacent said drive block and having a horizontally extendable and retractable shaft.

13. The system of claim 9, wherein said rotary actuator assembly comprises:

an actuator support structure secured to said vertical lift mechanism and including two substantially parallel guide plates extending between a base plate, each of said parallel guide plates constrained and guided by a linear bearing to restrict said each guide plate to movement in said vertical direction; and

a rotary actuator secured to said base plate and having an output shaft capable of at least 180 degrees of rotation.

14. The system of claim 13, wherein said rotary actuator is selected from a group consisting of electromagnetic actuators, piezoelectric actuators, and pneumatic actuators.

15. The system of claim 14, wherein said rotary actuator comprises a stepper motor configured for open-loop control.

16. The system of claim 13, wherein said rotary actuator includes a housing having a mounting flange.

17. The system of claim 16, wherein said rotary actuator includes a rotary position sensor associated with said housing.

18. The system of claim 9, wherein said tray manipulator comprises:

two substantially parallel extensions, each of said parallel extensions configured to engage an elongated side notch on said tray carrier; and

a connecting plate extending between and generally perpendicular to said two parallel extensions, said connecting plate configured for attachment to said rotary actuator assembly.

19. The system of claim 18, wherein each of said two parallel extensions includes an upper end having opposing notched edges, said opposing notched edges bracketing a central protrusion sized and located to closely mate with one of said elongated side notches on said tray carrier.

20. The system of claim 18, further comprising a bushing disposed on said connecting plate configured for said attachment to said rotary actuator assembly.

21. The system of claim 9, further comprising at least one sensor configured to sense a relative angular position of said tray manipulator.

22. The system of claim 21, wherein said at least one sensor is selected from a group consisting of rotary position sensors, non-contact proximity sensors, and contact-type proximity sensors.

23. The system of claim 8, wherein said input shuttle assembly and said output shuttle assembly each comprises:

a frame defining a vertical, rectangular tray stack volume of like length and width dimension to trays receivable in said tray carrier, said frame comprising four frame members, each of said four frame members including a vertically extending notch defining a comer of said tray stack volume, wherein said notches of two of said frame members differ in depth from said notches of another two of said frame members, and said frame members are spaced so that, in combination with said differing notch depths, said frame is adapted to receive trays in only one rotational orientation;

a plurality of tray support element actuators, one tray support element actuator of said plurality of tray support element actuators secured to each of said four frame members; and

a tray support element associated with each of said one tray support element actuators, each of said tray support elements biased inwardly towards said tray stack volume and extendable therefrom by said associated tray support element actuator.

24. The system of claim 23, wherein said tray support element actuators comprise air cylinders.

25. The system of claim 23, wherein said one rotational orientation of said output shuttle assembly is opposite said one rotational orientation of said input shuttle assembly.

26. The system of claim 8, further comprising:

mutually cooperative physical structures disposed on an upper surface of said tray transport and a lower surface of said tray carrier adapted to align said tray carrier on said tray transport, wherein portions of said mutually cooperative physical structures provide a fulcrum for tilting of said tray carrier with respect to said tray transport;

a cutout formed on said tray transport, wherein said tray transport is generally rectangular in shape and said cutout comprises a corner severed therefrom proximate said fulcrum; and

a lifting device extendable from a location below said tray carrier and adjacent a longitudinal end of said tray transport to contact said tray carrier at a location remote from said fulcrum, wherein said tray transport is of lesser longitudinal extent that said tray carrier.

27. The system of claim 26, wherein said mutually cooperative physical structures comprise:

a plurality of substantially hemispherical protrusions extending upwardly from an upper surface of said tray transport; and

a plurality of substantially hemispherical recesses extending into a lower surface of said tray carrier located and sized to receive at least portions of said substantially hemispherical protrusions.

28. The system of claim 27, further comprising:

an additional substantially hemispherical recess disposed on said lower surface of said tray carrier at a location beyond a longitudinal extent of said tray transport and proximate a longitudinal end of said tray transport opposite said cutout of said tray transport;

an element extendable upwardly from said lifting device to engage said additional substantially hemispherical recess, said element including a substantially spherical protrusion on an end sized to be received in said additional substantially hemispherical recess, wherein said element is extendable to a degree to lift said tray carrier at said location of said additional substantially hemispherical recess.

29. The system of claim 28, wherein said lifting device comprises an air cylinder having said element extendable upwardly therefrom.

30. The system of claim 26, further comprising a part movement facilitator located for contact with said tray carrier when said tray carrier is in a tilted position.

31. The system of claim 30, wherein said part movement facilitator is selected from a group consisting of a vibrator and a device configured for intermittent contact with said tray carrier.

32. The system of claim 8, further comprising:

a vertically extendable and retractable lift mechanism located within a tray stack volume of said input shuttle assembly and configured to engage and vertically move a tray located in said tray stack volume; and

a vertically extendable and retractable lift mechanism located within a tray stack volume of said output shuttle assembly and configured to engage and vertically move a tray located in said tray stack volume;

wherein said horizontal path of said transport actuator extends from said tray stack volume of said input shuttle assembly to said tray stack volume of said output shuttle assembly.

33. The system of claim 32, wherein said lift mechanism of said input shuttle assembly and said lift mechanism of said output shuttle assembly each comprises:

a horizontally movable drive wedge element having an inclined upper surface;

a dual-action drive mechanism configured to horizontally move said drive wedge element;

a dual-action stop mechanism configured and located to selectively limit travel of said drive wedge element;

a vertically movable slave wedge element having an inclined lower surface of like angle of inclination to said inclined upper surface of said drive wedge element;

a linear bearing configured to horizontally constrain said slave wedge element permitting substantially only vertical movement thereof; and

a lift structure secured to said slave wedge element and extending upwardly therefrom including two substantially parallel side plates laterally spaced a greater distance than a width of said tray transport and laterally spaced a greater distance than a portion of reduced width of said tray carrier.

34. The system of claim 33, wherein said dual-action drive mechanism comprises a pneumatically actuated drive block to which said drive wedge element is mounted, said drive block being slidable on at least one guide shaft.

35. The system of claim 33, wherein said dual-action stop mechanism comprises a dual-action air cylinder adjacent said drive block and having a horizontally extendable and retractable shaft.

36. The system of claim 8, wherein the laser marking station comprises:

a substantially bottomless enclosure located above the transport actuator; and

a single laser marking head housed within said enclosure and having a mark field.

37. The system of claim 36, wherein said tray carrier is sized and shaped to substantially correspond to an opening in said substantially bottomless enclosure of said laser marking station so as to provide a substantially light-safe closure for said opening when inserted thereinto.

38. The system of claim 37, further comprising:

a reduced width portion on said tray carrier defined by mutually longitudinally coextensive elongated notches in parallel sides thereof; and

two substantially parallel extensions extending upwardly from said rotational lift mechanism configured to engage said tray carrier at said reduced width portion, each of said two parallel extensions being sized to substantially prevent light leakage from said enclosure in a vicinity of said reduced width portion of said tray carrier.

39. The system of claim 37, further including at least one sensor associated with said enclosure for confirming presence of said tray carrier within said opening of said enclosure in a position effecting said substantially light-safe closure.

40. The system of claim 39, wherein said at least one sensor is responsive to a magnetic element located on said tray carrier.

41. The system of claim 8, further comprising at least one inspection camera located between said input shuttle assembly and said laser marking station.

42. The system of claim 8, further comprising at least one inspection camera located between said laser marking station and said output shuttle assembly.

43. The system of claim 8, further comprising:

an inspection camera located between said input shuttle assembly and said laser marking station; and

another inspection camera located between said laser marking station and said output shuttle assembly.

44. The system of claim 8, wherein said tray carrier is substantially rectangular and includes a substantially planar upper surface having upwardly-extending stops at each corner thereof configured for at least partially restricting movement of a tray disposed on said upper surface of said tray carrier.

45. A method of laser marking a plurality of IC packages carried in a tray located adjacent a laser marking head, comprising:

positioning a first portion of said plurality of IC packages in a mark field of said laser marking head;

laser marking said first portion of said plurality of IC packages;

rotating said tray to position a second portion of said plurality of IC packages in said mark field; and

laser marking said second portion of said plurality of IC packages.

46. The method of claim 45, wherein:

said first portion of said plurality of IC packages comprises IC packages carried in one longitudinal half of said tray and said second portion of said plurality of IC packages comprises IC packages carried in another longitudinal half of said tray; and

said rotating said tray to position said second portion of said plurality of IC packages in said mark field comprises rotating said tray approximately 180 degrees.

47. The method of claim 46, further comprising rotating said tray another approximately 180 degrees after said laser marking of said second portion of said plurality of IC packages.

48. The method of claim 45, further comprising positioning said tray at a laser focal length.

49. A method of laser marking IC packages carried in trays, comprising:

transporting a tray bearing IC packages to a location adjacent a laser marking head;

positioning a first portion of said IC packages in a mark field of said laser marking head;

laser marking said first portion of IC packages;

rotating said tray to position a second portion of said IC packages in said mark field;

laser marking said second portion of IC packages; and

transporting said tray bearing IC packages away from said laser marking head.

50. The method of claim 49, further comprising positioning said tray bearing IC packages at a laser focal length.

51. The method of claim 49, wherein:

said transporting a tray bearing IC packages to a location adjacent said laser marking head comprises transporting said tray in a first tray orientation; and

said transporting said tray bearing IC packages away from said laser marking head comprises transporting said tray in a second tray orientation opposite said first tray orientation.

52. The method of claim 51, further comprising:

supplying said tray bearing IC packages from a stack of trays bearing IC packages keyed to said first tray orientation; and

receiving said tray bearing IC packages into a stack of trays bearing IC packages keyed to said second tray orientation.

53. The method of claim 49, further comprising inspecting said IC packages prior to said laser marking said first portion of IC packages.

54. The method of claim 49, further comprising inspecting said IC packages after said laser marking said second portion of IC packages.

55. The method of claim 49, wherein each of said IC packages disposed in said tray bearing IC packages is disposed in a tray cell, and further comprising tilting said tray bearing IC packages to align said each IC package to a common corner of a respective one of said tray cells.

56. The method of claim 55, further comprising tapping said tray to overcome friction between said each IC package and said respective tray cell.