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The pad and wafer are pressed together by a dynamic polishing head and held in place by a plastic retaining ring. The dynamic polishing head is rotated with different axes of rotation (i.e., not concentric). This removes material and tends to even out any irregular topography, making the wafer flat or planar. This may be necessary to set up the ...
The optional second step (for bare silicon wafers) is a short immersion in a 1:100 or 1:50 solution of aqueous HF (hydrofluoric acid) at 25 °C for about fifteen seconds, in order to remove the thin oxide layer and some fraction of ionic contaminants. If this step is performed without ultra high purity materials and ultra clean containers, it ...
DISCO Corporation (株式会社ディスコ, Kabushiki-gaisha Disuko) is a Japanese precision tools maker, especially for the semiconductor production industry.. The company makes dicing saws and laser saws to cut semiconductor silicon wafers and other materials; grinders to process silicon and compound semiconductor wafers to ultra-thin levels; polishing machines to remove the grinding damage ...
These wafers are then polished to the desired degree of flatness and thickness. In the past, conventional circular saws were used during the 1950s and 1960s, followed by inner diameter saws in the 1970s and 1980s. These saws had diamond particles embedded into their blades to cut silicon. Multi-wire saws were introduced during the early 2000s.
Wafers grown using materials other than silicon will have different thicknesses than a silicon wafer of the same diameter. Wafer thickness is determined by the mechanical strength of the material used; the wafer must be thick enough to support its own weight without cracking during handling. The tabulated thicknesses relate to when that process ...
Etching a (100) silicon surface through a rectangular hole in a masking material, like a hole in a layer of silicon nitride, creates a pit with flat sloping {111}-oriented sidewalls and a flat (100)-oriented bottom. The {111}-oriented sidewalls have an angle to the surface of the wafer of:
Porous silicon was discovered by accident in 1956 by Arthur Uhlir Jr. and Ingeborg Uhlir at the Bell Labs in the U.S. At the time, the Uhlirs were in the process of developing a technique for polishing and shaping the surfaces of silicon and germanium. However, it was found that under several conditions a crude product in the form of thick ...
The wafers can be cleaned using H 2 O 2 + H 2 SO 4 or oxygen plasma. The cleaned wafers are rinsed with DI water and dried at elevated temperature, e.g. 100 to 200 °C for 120 min. [17] The adhesion promoter with a specific thickness is deposited, i.e. spin-coated or contact printed on the wafer to improve the bonding strength.