Processing flow of silicon ingots in the semiconductor industry
In the stage of single crystal silicon wafer preparation, silicon ingots need to be processed into raw silicon wafers or bare silicon wafers with high surface accuracy and surface quality to prepare for the flattening of processes such as photolithography in the first half of the IC process. An ultra-smooth and damage-free substrate surface is required here.
For silicon wafers with a diameter of ≤200mm, the traditional silicon wafer processing process is:
Single crystal growth → cutting → outer diameter barrel grinding → flat edge or V-groove processing → wafering → chamfering → grinding → etching → polishing → cleaning → packaging.
Planting: The purpose is to cut off the head and tail of the single crystal silicon ingot and the part that exceeds the customer’s specifications, split the single crystal silicon rod into a length that can be processed by the slicing equipment, and cut the test piece to measure the resistivity and oxygen content of the single crystal silicon rod. Quantity.
The process traditionally uses a diamond band saw or a single diamond wire to cut. In recent years, after the emergence of endless diamond wire cutting, a large-scale replacement of traditional cutting equipment has emerged.
Outer diameter grinding: Since the outer diameter surface of the single crystal silicon rod is uneven and the diameter is larger than the specified diameter specification of the final polished wafer, a more accurate diameter can be obtained by outer diameter rolling.
Flat edge or V-groove processing: It is specified to be processed to the reference plane, as well as the flat edge or V-groove with a specific crystal direction on the single crystal silicon support.
Wafering: refers to cutting the single crystal silicon rod into thin slices with precise geometric dimensions.
Chamfering: refers to trimming the sharp edge of the cut wafer into an arc to prevent chip edge cracking and quality defects
Grinding: refers to removing the saw marks and surface damage layer caused by slicing and grinding wheel grinding by grinding, effectively changing the warpage, flatness and parallelism of the single product silicon wafer, and reaching the specifications that can be processed by the polishing process.
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