This factory area covers the inspection, testing, sorting and binning of LED die according to their quality and electro-optical performance values. From each processed wafer a distribution of die is achieved. UNIROYAL, as company policy, championed the development of a unique set of capabilities that it presents to our customers as: Package Ready Known Good Die.

LEDs are current-driven, not voltage-driven, semiconductors. Drive current and light output are directly related. UNIROYAL, for its characterization testing of LED die, conducts these tests at the industries' standard 20 mA DC drive condition.

UNIROYAL has developed extensive automated test and characterization tools that are used to define LED performance from Whole Patterned Wafers through to specified tested and binned die on tape.

The levels of product currently offered are: Whole Undiced Wafers (Thinned or Unthinned) that are Sample Tested (shipped in pucks); Diced Wafers of Die that are either Sample Tested or 100% Tested (with ASCII Data File provided) (presented and shipped on tape/expander rings); and die that are 100% Tested and Sorted according to defined parameters: Known Good Die (KGD).

UNIROYAL LEDProbe™ Wafer Testing: Individual wafers (undiced and/or diced) are loaded via vacuum tip and positioning mechanisms onto a vacuum chuck. Once loaded the LEDProbe positions the probe head to encompass multiple die at a time. The LEDProbe is also equipped with an individual die “Capture Mask ”, that automatically sequences through the captured die, recording electro-optic values for each die in a computer Test Data File. “Sample ” testing tests selected (North, East, South, West and centralized) die sites scattered throughout the wafer. All values are recorded, a wafer map stored, and a yield value is determined by formula based upon the data obtained and an algorithm determined by the product description which is preprogrammed.

The LEDProbe can also be used to test 100% of the die sites on each wafer. Data from this method is captured and shipped with each individually tested wafer in the form of an ASCII diskette. Customers using this test level option use the ASCII file to program their LED die pick and place equipment with the supplied test data file and “sort” at the time of packaging.

UNIROYAL LEDSort™ Die Testing: Bare die are picked by a specialized collet and “read” platform system containing an integrated photonic receiver and electrode probe(s) and/or plate. After the die is “picked” and in transition to be “placed”, the LEDSort tests the LED die, and then after test places it based upon its’ individually read performance criteria, onto its’ applicable “bin” blue-film tape. Optical measurements are conducted by a ulti-wavelength spectrometer that measures brightness and chromaticity.

Electricals are conducted by a Multimeter. “Transfer”of the die is completed through preprogrammed recognition software contained within that directs the placement of die to a defined classification “rank” adhesive coated blue-film square. Up to seven (7) film squares/“ranks” can be accommodated at one time. Multiple wafers are used to populate each film square with a die count of from 8 to 10K per tape. Wafer differentiation is provided in the form of a die “space” row purposely left blank, before the next wafer’s die is placed. Output from the UNIROYAL LEDSort provides customers with fully binned Known Good Die (KGD).

Visual Inspection: Visual inspection is currently conducted manually under 20X magnification. Individual die are inspected for damage, defects and contamination as defined by the UNIROYAL Product Specification defect identification appendix. This process removes all defective die prior to shipment.