Supplying die attach alloys and thin film products.
At the heart of every wireless device is a semiconductor. The semiconductor substrate is often chosen by the operating characteristics and applications for the device. Currently Silicon and GaAs are the leading substrates for wireless devices, but as higher frequencies and powers are demanded, other substrates such as SiGe, SiC and GaN must be considered. Ohmic contacts form the basis of connecting power to and from a semiconductor device and are critical to predictable operation.
At the interface between two unlike materials, the resistance to electron transport across the interface may become a function of the applied voltage. For each type of device or substrate material, different metallization schemes are used to form the ohmic contact. Often with the use of these new substrates the ohmic contact metallization alloy needs to be adjusted. Williams has worked with several fabrication companies and has developed and optimized alloy ratios for the contact metallization.
Williams Products Used
Williams products are intrinsically involved in the production of ohmic contacts for various semiconductor substrates. Sputtering targets featuring SFG™ technology and metal evaporation materials featuring EVAPro™ technology are used for metallization of the wafers at the contact surface for adhesion, galvanic corrosion protection, stress minimization and prevention of oxidation. Some of the common materials utilized include:
- Au
- AuSn*
- AuGe*
- AuZn
- Ti
- Cr
- Ti
- Pt
- Pd
- Ni
- NiCr
* Brittle materials such as AuGe and AuSn sputtering targets are manufactured using VCT™ technology.
Williams also offers a comprehensive array of alloy preforms for die attach. Typically AuSn and AuGe based alloys are used for the die attach. Williams is able to provide custom reflow profiles based on your custom application, to ensure maximum yields and throughput.
Williams also offers a full array of backing plate designs and internal services, including the ability to replace, refurbish, repair and design backing plates using CAD/CAM. Our target bonding facilities are located throughout the world, supplying industry-leading bonding services and assuring timely turnarounds.
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