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Etching is a critically important process module in fabrication, and every wafer undergoes many etching steps before it is complete. For many etch steps, part of the wafer is protected from the etchant by a "masking" material which resists etching. In some cases, the masking material is a photoresist which has been patterned using photolithography.
Early semiconductor processes had arbitrary names for generations (viz., HMOS I/II/III/IV and CHMOS III/III-E/IV/V). Later each new generation process became known as a technology node [17] or process node, [18] [19] designated by the process' minimum feature size in nanometers (or historically micrometers) of the process's transistor gate ...
The dry etch is then performed so that structured etching is achieved. After the process, the remaining photoresist has to be removed. This is also done in a special plasma etcher, called an asher. [14] Dry etching allows a reproducible, uniform etching of all materials used in silicon and III-V semiconductor technology. By using inductively ...
Wafer fabrication is a procedure composed of many repeated sequential processes to produce complete electrical or photonic circuits on semiconductor wafers in a semiconductor device fabrication process. Examples include production of radio frequency amplifiers, LEDs, optical computer components, and microprocessors for computers. Wafer ...
NEC and Toshiba used this process for their 4 Mb DRAM memory chips in 1986. [47] Hitachi, IBM, Matsushita and Mitsubishi Electric used this process for their 4 Mb DRAM memory chips in 1987. [37] Toshiba's 4 Mb EPROM memory chip in 1987. [47] Hitachi, Mitsubishi and Toshiba used this process for their 1 Mb SRAM memory chips in 1987. [47]
To etch through a 0.5 mm silicon wafer, for example, 100–1000 etch/deposit steps are needed. The two-phase process causes the sidewalls to undulate with an amplitude of about 100–500 nm . The cycle time can be adjusted: short cycles yield smoother walls, and long cycles yield a higher etch rate.
Indium and gallium are group III elements of the periodic table while arsenic is a group V element. Alloys made of these chemical groups are referred to as "III-V" compounds. InGaAs has properties intermediate between those of GaAs and InAs. InGaAs is a room-temperature semiconductor with applications in electronics and photonics.
The etching solution usually has no preferred direction of attacking the substrate, therefore isotropic etching takes place. In semiconductor engineering, however it is often required that the sidewalls of the etched trenches are steep. This is usually realized with methods that operate in the gas-phase such as reactive ion etching. These ...