Recently, the demand for ultra-thin silicon wafers has overgrown due to the rapid miniaturization of electronic devices.
FREMONT, CA: Wafer thinning is a step in the fabrication of semiconductors that tries to minimize wafer thickness. This enables the creation of ultra-thin wafers for more complex integrated circuits (ICs) to meet the evolving demands of the electronic market to manufacture tiny, portable gadgets.
Wafer thinning is a complicated but necessary step in the fabrication of semiconductors. The thinning and dicing of semiconductor wafers into microscopic chips for electronic devices involves highly complex machinery and specialized surroundings.
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Wafer thinning, also known as wafer backgrinding, is a phase in the manufacture of semiconductor devices in which wafer thickness is lowered to enable stacking and high-density packaging for compact electronic devices.
Therefore, wafer thinning removes material from the rear of a wafer until the appropriate thickness is reached.
The purpose of wafer back grinding is to remove a specified quantity of material from the wafer's substrate, typically silicon. It is advantageous to the requirements of the device packaging process, heat dissipation, and chip size. Consequently, the benefits of wafer thinning include—lowering thermal resistance, enhancement of gadget functionality, enhancement of dependability, and reducing total package height.
Reducing die stress caused by mismatches between the silicon die coefficient of thermal expansion (CTE) and the board materials.
Portable and lightweight technologies, such as portable music players, smartphones, and USB memory sticks, are becoming increasingly prevalent in contemporary electronics. This development would only be conceivable with the miniaturization of their constituent parts. Before wafer dicing (the separation of individual microchips), this step requires the grinding or thinning of the backside of wafers. Wafers are typically 750 m thick to provide mechanical stability and prevent warping during high-temperature manufacturing. Nevertheless, due to wafer backgrinding, wafers are often thinned to 75 or 50 m.
Mechanical grinding, chemical-mechanical planarization (CMP), wet etching, and atmospheric downstream plasma (ADP) with dry chemical etching are methods for wafer thinning (DCE). Conventional grinding and chemical-mechanical planarization are the two most popular processes for wafer thinning.
Wafer Thinner with Standard Grind
Conventional grinding is a mechanical procedure for wafer thinning that typically employs a diamond and resin-bonded grind wheel mounted on a high-speed spindle to remove material. The grind recipe dictates the spindle's speed and the material removal rate, ultimately leading to the wafer's final thickness.
Before mechanical grinding begins, a layer of grinding tape is adhered to the front of the wafer to isolate its contents from damage during thinning. The wafer is kept in place by a revolving porous ceramic vacuum chuck, with the wafer's reverse side facing the grinding wheel. Grinding wheels and chucks are rotated simultaneously while deionized water is sprayed on the wafer to cool and wash away the material particles.
This is the most common thinning method employed today, and it is advantageous due to its precision and high thinning rate.
Two phases comprise the mechanical grinding procedure.
Coarse Grinding: This is where most of the material is removed, with removal rates of approximately 5m/sec.
Fine grinding: This features a 1200 to 2000 grit sand and poligrind fine grind, which typically eliminates 30m of material gathered from 1m or less per second. Here is where the wafers receive their final coating.
