Cleaving Silicon Wafers

Cleaving Silicon Wafers

PAM XIAMEN offers Cleaving Silicon Wafer, which is cut by multi-wire cutting technology. Here is the cleaving silicon wafer specs:

Cleaving (100) silicon wafers

Cleaving (111) silicon wafers

cleaving silicon wafer

Here comes a question: how to cleave a silicon wafer? At present, the silicon wafer cleaving technology mostly adopts the multi-wire cutting technology, which has higher cutting efficiency, lower cost and less material loss than the previous inner circle cutting. Currently, the thinnest silicon wafer can be cut is about 200um.

Cleaving silicone wafer is an important step in silicone wafer processing, which directly affects the surface crystal orientation, thickness, surface roughness, and warpage of the silicon wafer. There may be wire breakage, downtime, uneven thickness, and excessive roughness in the cleave silicon wafer manufacturing process. 

Silicon wafer cutting is the most critical process point in the silicon wafer processing process. Its processing technology and processing quality directly affect the overall production and subsequent device process preparation. Therefore, there should be strict process requirements for cleave a insulate bulk silicon wafer.

1. Technical Principles for Cleaving Silicon Wafer with a Orientation of (111) or (100)

The technical principles to be observed in the process of cleaving Si wafer:

The section integrity is good, eliminating the traces of drawing and printing;

The cutting precision and the surface parallelism should be high, and the thickness error should be small;

Improve the yield rate, narrow the cutting gap, and reduce material loss;

Improve cutting speed, improve production efficiency, realize intelligent control, and automatically cut;

It is necessary to ensure the fluidity of the cutting fluid to take away the capacity and finely divided SiC particles in time.

2. Main Parameters of the Multi-wire Cutting Process for Cleaving Silicon Wafers

Cleaving Method Free Grinding Process
Cut Surface Features Imprint
Wire Cutting Wire Diameter 180um
Damage Depth 5-15um
Productivity 110-500cm2/h
Number of Cuts Per Time 200-1100
Kerf Loss 150-210um
Minimum Cutable Silicon Wafer Thickness 200um
Maximum Cutting Silicon Rod Diameter 300um
WARP 5-10um
TTV <15um
Cutting Residual Stress Small

 

3. Technical Difficulty of Cleaving Silicon Wafer by Multi-wire Cutting Process

Analyze the influence of parameters, such as the wire running speed of the steel wire, the feed speed of the workpiece, the initial tension of the steel wire, the concentration of the cutting fluid and the good grain size of the abrasive on the slicing process:

a) For free abrasive wire cutting, steel wire cutting generally does not cause instability. The faster the wire travel speed, the greater the vibration of the steel wire; the smaller the density of the steel wire, and the greater the tension during processing; and the higher the speed at the critical point, the greater the initial tension of the steel wire. The smaller the vibration of the steel wire.

b) The smuggling speed of the steel wire is an important factor that affects the vibration of the steel wire and the surface roughness and cutting accuracy of the processed silicon wafer. Too small a wire speed will increase the vibration of the steel wire and increase the cleave Si wafer surface roughness. A large and appropriate wire feeding speed of the steel wire is beneficial to slow down the vibration of the steel wire and reduce the surface roughness and TTV of the 100 and 111 silicon wafer cleaving.

c) The greater the wire speed of the workpiece, the greater the vibration of the steel wire, which increases the cleave Si wafer roughness and TTV.

d) The greater the initial tension of the steel wire, the smaller the vibration of the steel wire during processing, the smaller the surface roughness of the cleaving Si wafer, and the smaller the TTV value.

e) The smaller the size of the abrasive grains, the more abrasive the steel wire will bring into the processing area during processing, and the smaller the surface roughness value and TTV of the cleaved silicon wafer.

f) The greater the concentration of the cutting fluid, the more abrasive the steel wire brings into the processing area during cleaving process of Si wafer, and the smaller the surface roughness value and TTV of the cleaving silicon wafer.

g) The larger the diameter of the silicon rod processed by free abrasive wire cutting, the longer the contact time between the steel wire and the workpiece, which increases the number of abrasives brought into the processing area by the steel wire to participate in cutting, and the corresponding effect of the abrasive on the steel wire. The greater the force will increase the vibration of the steel wire, which will increase the cleaved Si wafer surface roughness.

4. Main Problems Existing in Multi-wire Cutting of Cleaving Silicon Wafers:

SiC particle: it is critical in silicon wafer cleaving process. The shape of silicon carbide particles affects cutting efficiency and yield. At present, SiC has high roundness and few edges and corners, which leads to a decrease in cutting efficiency and a decrease in yield;

PEG polyethylene glycol liquid: crystalline silicon cutting fluid is compounded with PEG as the main additive and other additives. PEG should have suitable adhesion indicators, good wettability, strong chip removal ability, good high suspension, high lubrication, high dispersion characteristics, and can meet the quality requirements and technical standards of the cutting fluid during the entire cleaving silicon wafer process.

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