The universal XBS200 platform allows for aligned wafer bonding of wafer sizes up to 200 mm. Its versatility and modular design offer maximum process flexibility in all permanent bonding tasks. A novel aligned wafer transfer method eliminates the complexity of traditional systems and offers consistent process results with excellent system availability. The XBS200 platform offers low cost of ownership for high-volume production of MEMS, LED and 3D advanced packaging.
Submicron alignment accuracy
Integrated metrology option
Unique laser pre-bond option
High process repeatability
Low cost of ownership
The XBS200 handles single wafers as well as aligned- and bonded wafer pairs by making use of a novel aligned wafer transfer method. It offers wafer cassette stations with integrated mapping and a camera-based optical pre-aligner with optional ID readers. An optional camera system allows to monitor and record the inside of the machine. A cyclic scheduling algorithm with automated throughput optimization ensures consistent timing of all processes and continuous run capability.
The XBA bond aligner delivers consistent submicron alignment accuracy for transparent or non-transparent wafers by using our proprietary inter-substrate-alignment (ISA) technology. Built-in fixed reference, global calibration and overlay verification ensure optimum repeatability. Global calibration wafers are an integral part of the system and make automated calibration and overlay verification simple and quick.
The XBA offers the option as novel functionality to locally bond a wafer pair via laser pre-bonding after alignment and before transferring it into the bond chamber. This helps to literally freeze the achieved alignment accuracy of the bond aligner.
The XB200 bond chamber is the process module version of the stand-alone XB8 bonder. It offers a wide parameter window and is therefore ideal for any thermo-compression bonding processes. Bond force options include a 60 kN and a 100 kN version and a temperature range of up to 550 °C is available. Reproducible process results from wafer to wafer achieve a consistently high product quality.
The capacitively coupled plasma offers highest process flexibility and repeatability for plasma-based wafer surface activation. Various process gases such as Ar, O2, N2 etc. can be used and are controlled via (mass flow controllers (MFCs). The gate-valve loading PL200 allows for full CMOS compatibility and can also be used for plasma cleaning of polymer residues.
The AC200 aqueous cleaner module offers various dispense system options including megasonic. The module also allows for optional backside rinse and N2 assisted spin-drying. Diluted cleaning chemistry such as NH4OH (<2%) is available in the basic configuration. Organic removal functionality using SC1 is available on request.
Integrated in-situ metrology functionality allows for fast process feedback. The MM200 therefore is the key for increased process control and yield improvement. The module can be configured for full-field IR void inspection and/or IR overlay measurement including multi-site capability with high throughput. The module offers in-line process control and provides closed-loop feedback to optimize the alignment results. The MM200 does not occupy a process module space.
A variety of materials are available for adhesive wafer bonding techniques utilizing polymers and adhesives, including epoxies, dry films, BCB, polyimides, and UV curable compounds.
Anodic wafer bonding involves encapsulating components on the wafer by means of ionic glass. In triple-stack bonding, three layers (i.e. glass-silicon-glass) are simultaneously bonded, enhancing both functionality and yield.
Eutectic wafer bonding takes advantage of the special properties of eutectic metals. Similar to soldering alloys, such metals melt already at low temperatures. This property allows planar surfaces to be achieved.
In order to control reflow of the eutectic material, eutectic bonding requires precise dosing of the bonding force and even temperature distribution.
Fusion bonding refers to spontaneous adhesion of two planar substrates with a dielectric material (typically silicon oxide) as the bonding layer. The process usually involves a proper surface activation that renders the substrates to be largely hydrophilic. Subsequently the substrates are aligned, brought into contact and finally tempered at elevated temperature.
Glass Frit Bonding
A glass frit bonding process involves screen-printing glass frits onto the bonding surfaces. This results in structures that are subsequently heated and fused when the two substrate surfaces are placed in contact. On cooling, a mechanically stable bond results.
Hybrid bonding is an extension of fusion bonding, so that in addition to the dielectric material also metallic structures can be found in the bonding interface, which are bonded by diffusion during the annealing process. Successful bonding requires very careful control of the metal structure topography.
Metal Diffusion Bonding
Metal diffusion bonding is based on Cu-Cu, Al-Al, Au-Au and other metallic bonds. In addition, the use of metal diffusion allows two wafers to be bonded both mechanically and electrically in a single step. The technique is required for bonding in 3D applications such as 3D stacking.
SLID bonding (solid-liquid inter-diffusion) is based on diffusion and the mixture of different metals. The melting temperature of the alloy after bonding is very much higher than the bonding temperature, which clearly widens the range of possible applications.