Laser marking system for dice carried in trays and method of operation

• US 6,417,484 B1
• Filed: 12/21/1998
• Issued: 07/09/2002
• Est. Priority Date: 12/21/1998
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micro Electronics Incorporated
• Inventors: Canella, Robert L., Ibarra, Tony T.
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): JOHNSON, JONATHAN J
• Application Number:
  US09/217,040
• Time in Patent Office: 1,296 Days
• Field of Search: 219/121.82, 219/121.68, 219/121.69, 219/121.67, 414/222.01, 414/222.13, 198/347.1
• US Class Current: 219/121.68
• CPC Class Codes: B23K 2101/007 Marks, e.g. trade marks
• CPC Class Codes: B23K 26/0838 by using an endless conveyor belt
• CPC Class Codes: H01L 21/67282 Marking devices

Abstract

A laser marking system for IC packages including a tray input shuttle assembly, a tray transport borne by a transport actuator for moving a cooperatively configured tray carrier carrying a tray of unmarked packaged ICs received from the tray input shuttle assembly to a tray output shuttle assembly over a transport actuator path extending under an open-bottomed enclosure of a laser marking station. The tray input shuttle assembly, laser marking station and tray output shuttle assembly each has associated therewith a sliding wedge-type lift mechanism for raising and lowering the tray carrier vertically with respect to the transport so as to facilitate tray loading of the tray carrier from a stack of trays on the tray input shuttle assembly, insertion and withdrawal of the tray carrier bearing a tray of packaged ICs for marking into and out of the marking station and unloading of a tray of marked packaged ICs from the tray carrier onto a stack of trays on the output shuttle assembly. The lift mechanisms and tray shuttle assemblies may each be driven by air cylinders. A method of operation of the laser marking system is also disclosed.

Claims

1. A method of marking a plurality of IC packages carried in a tray, comprising:

providing at least one tray carrying a plurality of discrete IC packages;

lowering the at least one tray and the plurality of discrete IC packages carried thereby from a first position to a second position;

moving the at least one tray and the plurality of discrete IC packages carried thereby horizontally to a third position;

raising the at least one tray and the plurality of discrete IC packages carried thereby to a fourth position;

marking the plurality of discrete IC packages carried by the at least one tray at the fourth position;

lowering the at least one tray and the plurality of discrete IC packages carried thereby to the third position;

moving the at least one tray and the plurality of discrete IC packages carried thereby horizontally to a fifth position; and

raising the at least one tray and the plurality of discrete IC packages carried thereby to a sixth position.

2. The method of claim 1, wherein the at least one tray comprises a plurality of vertically stacked trays at the first position and further comprising removing a lowermost tray from the plurality of stacked trays to lower the removed tray to the second position and proceed the removed tray therefrom through the third, fourth, fifth and sixth positions.

3. The method of claim 2, further comprising raising the removed tray to the bottom of a vertical stack comprising a plurality of trays at the sixth position.

4. The method of claim 1, further comprising raising the at least one tray and the plurality of discrete IC packages carried thereby into an enclosure at the fourth position and substantially concurrently sealing the enclosure against light leakage therefrom.

5. The method of claim 1, wherein the marking is effected by laser light.

6. The method of claim 5, wherein the marking is effected substantially simultaneously in two adjacent fields, each of the fields approximating one-half of an area of the at least one tray and containing approximately half of the plurality of discrete IC packages.

7. The method of claim 6, further comprising inspecting a last discrete IC package carried by the at least one tray and marked in each of the two fields between the third and fifth positions.

8. The method of claim 1, further comprising tilting the at least one tray and plurality of discrete IC packages carried thereby before the at least one tray reaches the fourth position.

9. The method of claim 8, further comprising imparting force to the at least one, tilted tray to cause the plurality of discrete IC packages carried in recesses in the at least one, tilted tray to reach a substantially common alignment for marking.