Confinement Chamber
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High Quality and Reliable Bond requires Oxygen Free Environment to Avoid Oxide formation during Bonding, especially at High Temperature. To address this requirement, S.E.T. has developed a Gas Confinement Chamber which prevents Pads and Bonding Medium Oxidation during the Bonding Sequence. Neutral Gas, like Nitrogen, is sufficient to prevent oxide formation.
For some applications like Infrared Sensor Focal Plane Arrays where two chips, the sensor and the read-out, are connected through high density Indium Micro Bump Array, native oxide is already present either on pads or bumps. |
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The oxide must be removed prior bonding to enable good wetting. In that case, the use of Reducing Gas, such as Forming Gas or Formic Acid Vapor, is necessary. Oxide removal is generally operated in a closed confinement under a Nitrogen flux saturated with formic acid vapor. In a closed and sealed chamber, it is easy to collect and recycle the gas to prevent environment contamination and to avoid any Oxygen intrusion into the chamber.
In order to keep all the standard functions of our hybridization equipment and especially the low contact force measurement applied to the components, we have developed a “Semi-Open” process chamber in which upper part never touch the lower part. A Non-Contact Virtual Sealing is used to ensure Gas Collection and prevent Oxygen intrusion.
This confinement can be used under Pure Nitrogen (N2), Nitrogen saturated with Formic Acid Vapor or other Process Gas. The Gas saturation is adjustable to adapt to the Process Requirements.
The Process Gas is injected around the components, while the bonding arm is in the bonding position offering a Cover to the Confinement System. To avoid Process Gas contamination in the environment, an exhaust ring collects the Gas out of the bonding area an contribute to the creation of a Uniform Gas Blanket. An additional Nitrogen Ring Block the Oxygen which might be sucked back in the Process area.
This system is subject of patents request.
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