Disco present newly developed fully-automatic die separator for small die
DISCO Corporation has recently showcased at SEMICON Japan 2016 the DDS2310, a fully-automatic die separator which specializes in the separation of small die.
Development Background
Recently, due to the wide use of sensors and MEMS devices as a result of the expansion of the IoT, the expectations for the stealth dicing (SD) process, which processes small die and reduces the street width, is rising. However, when separating a wafer after SD into small die (1x1 mm or less), conventional die separators struggle to maintain a kerf width required for the next process: die bonding.
With this in mind, DISCO has developed DDS2310, a die separator which specializes in the separation of small die. By optimizing the heat shrink mechanism, DDS2310 is able to maintain a wider kerf width compared to the existing equipment, even when separating into small die, and improves image recognition failures and pick-up failures in the next process.
What is a Die Separator? A die separator is equipment used to separate a mounted workpiece into die by expanding the dicing tape. DAF (die attach film, which is required to secure die when stacking thin die) and an SD-processed wafer (with a modification layer formed inside the wafer by focusing a laser onto the wafer) is attached to the tape. The DAF and wafer are then separated by conducting tape expansion (cool expansion) on a cool-expansion stage. Then, expansion is performed again on the heater expansion stage to maintain the kerf. The tape sag generated at the circumference of the tape is eliminated by applying a heat of 200ºC or higher and shrinking the tape. By doing this, the kerf width after separation is maintained and image recognition failures during die bonding in the next process are reduced, enabling the smooth transfer of the tape frames to the next process without changing the tape.
Die Separator Process Flow
(1) The push-pull arm pulls the workpiece out from the cassette and transfers the workpiece to the frame centering stage.
(2) The workpiece is aligned on the frame centering stage and then is transferred to the intermediate stage.
(3) The workpiece is transferred to the cooler expansion stage and cool expansion is performed.
(4) The workpiece is transferred to the heater and expansion stage, and heat shrinking is performed.
(5) The workpiece is transferred to the spinner stage, where it is cleaned and dried.
(6) The workpiece is transferred to the UV irradiation stage and UV irradiation is performed.
(7) The push-pull arm returns the workpiece to the cassette.
Product Features
When separating small die (1x1 mm or less), a sufficient kerf width can be maintained for the next process by using the new heat shrink mechanism.
New Mechanism (1): New Table for Kerf Width Expansion
The existing room-temperature expansion table inside the heater expansion stage has been replaced with a heater table.
The dicing tape is heated when expanding and becomes easy to expand, increasing the kerf width. By doing so, a sufficient kerf width for small die can be maintained.
By expanding the heater table's vacuum area, the wafer can be secured right through to the circumference of the table. The vacuum area can be selected from two types of vacuum lines, and the tape expansion amount can be increased by securing the wafer through to the circumference of the table when separating small die (1x1 mm or less), achieving an increased kerf width.
New Mechanism (2): New Heater for Maintaining Kerf Width
The tape shrink performance has been improved by applying heat in a wider area using a new heater instead of the existing hot-air heater. Due to its stability in temperature and a shorter time required for the temperature to rise, DDS2310 achieves efficient heat shrinking.
