After the wafer has gone through the front-end process, the chip preparation is completed, and it needs to be cut to separate the chips on the wafer and finally packaged; in addition, there are also some processes and tests that require the pure silicon wafer substrate to be cut into small square pieces for use.

Figure 1. Characteristics of UV and blue films UV and blue films

Both UV film and blue film are sticky. The degree of stickiness is generally expressed by the sticky peeling degree, usually in units of N/20 mm or N/25 mm. 1 N/20 mm means that the test strip is 20 mm wide and the force required to peel it off the test board at a peeling angle of 180 degree is 1 N.

UV film is a special coating applied to the surface of a PET film substrate to block ultraviolet light and short-wavelength visible light. Figure 2 is a general UV film structure diagram.

Figure 2. UV film structure

The viscosity of high-viscosity UV film is 5000mN/20mm ~ 12000mN/20mm before ultraviolet irradiation. After ultraviolet irradiation, the peeling viscosity is below 1000mN/20mm;

The peeling viscosity of low-viscosity UV film is about 1000mN/20mm before ultraviolet irradiation. After ultraviolet irradiation, the peeling viscosity drops to about 100mN/20mm.

After ultraviolet irradiation, there will be no residual glue on the wafer surface of the low-viscosity UV film, and the grain is easy to remove.

Blue film is usually called electronic grade tape. It is relatively cheap. It is a blue film with constant viscosity. Its viscosity peeling degree is generally 100~3000mN/20mm. It will produce residual adhesive due to the influence of temperature. In contrast, UV film is more stable and has less residual adhesive than blue film.

However, if the feeding speed of the slice is greatly increased, the possibility of the edge of the small chip peeling will increase. Therefore, the number of rotations of the impeller should be controlled at about 30,000 times per minute.

To take on new slicing challenges, collaboration between slicing systems and blades is necessary. This is especially true for high-end applications.