What is wafer bonding in MEMS?
Wafer bonding is a packaging technology on wafer-level for the fabrication of microelectromechanical systems (MEMS), nanoelectromechanical systems (NEMS), microelectronics and optoelectronics, ensuring a mechanically stable and hermetically sealed encapsulation.
Which technique can be used for bonding wafers?
Wafer bonding is a process by which two mirror-polished wafers of any materials adhere to each other at room temperature without the application of any macroscopic gluing layer or external force. The bonding is achieved through van der Waals force.
Why do we use wafer bonding?
Wafer bonding is a packaging technology on wafer level for the fabrication of micro electromechanical systems [MEMS], ensuring a mechanically stable and hermetically sealed encapsulation. Need of wafer bonding: The long term stability and reliability of the functional elements depends on the encapsulation process.
How do you bond 2 silicon wafers?
If both wafer surfaces are sufficiently flat and hydrophilic, they will bond together at room temperature with simple pressure to squeeze out the air and/or water. on the surface of a Si wafer can be stripped with a dilute aqueous HF etch solution.
What is a carrier wafer?
Adapter carrier wafers are either surface processed glass or silicon wafers with patterned pocket(s) or silicon wafers permanently bonded to borosilicate glass rings that have been patterned according to the dimensions of the substrate.
What is hybrid bonding?
Hybrid bonding extends fusion bonding with embedded metal pads in the bond interface, allowing for face-to-face connection of wafers. This special case is called hybrid bonding. The main applications for hybrid bonding include CMOS image sensors, memory as well as 3D system-on-chip (SoC).
What is adhesive bonding process?
Adhesive bonding is a process in which joining between two or more parts is accomplished by the solidification or hardening of a non-metallic adhesive material, placed between the faying surfaces of the parts (O’Brien, 1991, p. 839).
Is a packaging technology on wafer level for the fabrication of MEMS?
Die-level packaging can be used as ordinary so that the wafer level in packaging can be a good method for MEMs technology….Consideration for MEMS packaging.
|Die-level packing||Wafer level packing|
|Common MEMS IC packaging technology||Peculiar for MEMS IC packaging|
What is fusion bonding?
Direct bonding, or fusion bonding, describes a wafer bonding process without any additional intermediate layers. The bonding process is based on chemical bonds between two surfaces of any material possible meeting numerous requirements.
What is silicon fusion bonding?
Silicon fusion bonding (SFB) is the joining together of two silicon wafers without the use of intermediate adhesives. Silicon fusion bonding presents major new possibilities in the design of silicon micromachined structures when combined with other available processing techniques.
What are the three requirements to achieve an adhesive bond?
The adhesive can also provide uniform distribution of stress and large stress-bearing areas. The basic processes of adhesive bonding include surface treatments, adhesive application, assembly and cure.
What are the disadvantages of adhesive bonding?
Disadvantages of adhesive bonding
- Requires careful substrate (adherent) surface preparation;
- Long mixing and curing time may be required;
- Importance of right joint design;
- Difficult disassembly of joined parts;
- Necessity to fixture (hold together) the joined parts during curing;
What type of bonding is used in MEMS?
Anodic bonding Since accidentally found in 1960s by P.R. Mallory, US battery company , anodic bonding has been the most widely used bonding method for MEMS, because it is easy, reliable and of high yield. In principle, anodic bonding can be done between electron-conductive materials and ion-conductive materials.
How to increase the bond strength of a wafer?
• After room temperature (RT) bonding (sometimes known as “tacking”), wafer pairs are usually given a thermal treatment to increase the bond strength. • This varies considerably, depending upon the application.
What are the factors that affect the reliability of sealed MEMS?
For anodic bonding, bonding temperature, high voltage, Na contamination and electrochemical O 2 generation may affect the reliability of sealed MEMS, and some techniques to solve related problems were given in this paper.
What are siloxane bonds in silicon wafers?
• Oxide Si–O–Si are called siloxane bonds. • Siloxane to silanol conversion is reversible up to ~425°C. • If both wafer surfaces are sufficiently flat and hydrophilic, they will bond together at room temperature with simple pressure to squeeze out the air and/or water. R. B. Darling / EE-527 / Winter 2013 Hydrophobic Surface Bonding in Silicon •SiO