Introducing the DGP8761 High Level Cleaning Specification:
Grinder for φ300 mm Wafers to Provide Better Cleanliness After Thinning
DISCO Corporation (Head Office: Ota-ku, Tokyo; President: Kazuma Sekiya) has developed the DGP8761*1 High Level Cleaning Specification. This fully automatic grinder has a unit which cleans a silicon wafer after thinning to the level of cleanliness to be able to reload it into the equipment in the wafer fabrication process of semiconductor manufacturing.
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*1 DGP8761 :
A grinder/polisher for φ300 mm wafers which conducts the grinding and polishing processes singlehandedly, with a design of 3 spindles and 4 chuck tables.
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Development Background
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DGP8761
High Level Cleaning Specification |
Devices using the TSV (through silicon via) process have attracted attention recently. For these devices, requests to put the wafer back into the wafer fabrication process for such as CVD (chemical vapor deposition) or dry etching, which requires a high level of cleanliness, after grinding and polishing of the assembly and testing process have been increasing.
Also in the field of the CMOS image sensor device with BSI (backside illumination) technology, minimizing particles on the ground or polished wafer surface is required since they have negative impact on quality. Thus, an even higher cleanliness is asked for in the wafers.
In order to satisfy these needs, DISCO has added the cleaning unit jointly developed with Shibaura Mechatronics, which has an excellent technical capability for cleaning, to the DGP8761, DISCO grinder/polisher widely introduced at manufacturing sites. This innovation enables enhancing the cleanliness of wafers after grinding and polishing. |
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Features of the DGP8761 High Level Cleaning Specification
| Example of cleaning result |
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| A KLA-Tencor SP1DLS is used to measure particles. |
<Various cleaning methods>
In addition to the cleaning of both wafer sides by scrubbing, which is the proprietary technology of Shibaura Mechatronics, this specification handles a wide range of methods including the cleaning using chemicals, such as ozone water or DHF (diluted hydrofluoric acid), in order to remove particles like slurry, organic substances, and metal impurities. This improves the cleanliness up to the level where 0.2 µm particles are 10 or less on the wafer surface, which could not be realized before.
<Prevention of particle adhesion due to wafer drying>
Since the surface of the wafer after grinding and polishing dries before cleaning, particles on the wafer adhere, so that their removal by cleaning becomes difficult. This cleaning unit adopts an edge clamp transport, which enables wet handling without touching the wafer surface, and enhances wafer cleanliness after grinding and polishing. |
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<Prevention of particles inside the machine>
This DGP8761 model introduces the handling module called EFEM*2 which is normally used in the equipment in the wafer fabrication process to load and unload wafers. In the machine, the grinding/polishing section, cleaning section, and EFEM section, whose particle level is different, are separated individually using shutters and the pressure balances among these sections are adjusted so that air flows only one direction from cleaner area to less clean area, thereby preventing adhesion of particles on the wafers.
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*2 EFEM (equipment front end module) :
An interface to load/unload wafers with outside of the equipment. A module which consists of the load port, wafer handling unit, and wafer handling chamber, and loads and unloads wafers while maintaining a local clean environment with the help of the FFU (fan filter unit).
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<Prevention of particles outside the machine>
This machine prevents particles from being discharged to the outside, based on the assumption that the machine is installed in a clean room for the wafer fabrication process, and meets Class 100 requirements.
Schedule
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Panel displays at SEMICON Japan 2009
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December 2009
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Production has already started and deliveries are available.
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