There are various problems such as front and back chipping during wafer dicing. This is a topic that cannot avoided in the dicing industry. How to solve the problem chipping of wafer saw ? We share our on-site dicing experience by in-depth research and technological accumulation, providing reference for semiconductor cutting practitioners.
We hope that semiconductor practitioners can gain inspiration from it, improve processing quality and efficiency, and achieve lower wafer cutting cost.
Front Chipping in Wafer Saw
Wafer surface chipping (front chipping) can be divided into three types: initial chipping/repeated cycle chipping/other chipping
1.Initial Chipping in Wafer Saw
It mainly refers to the front chipping of the product that occur during the pre cutting stage of the new blade installation, which may be caused by three aspects:
① Dicing Blade installation tilted;
② The dicing blade is not truly round;
③ The diamond is not fully exposed and there are no grooves.
Solution：
①Check the accuracy of blade installation;
②Dress the blade, adjust the concentricity of the blade;
③Perform pre cutting again to fully expose the diamond.
2.Cycle Chipping in Wafer Saw
There are three main reasons for repeated cycle chipping during the cutting process:
- The blade surface is impacted.
- There are large diamond protrusions on the surface of the blade.
- There are other impurities adhering to the surface of the blade.
Solution:
- Check if there are any product flying material impact marks on the surface of the blade.
- Observethe blade edge part whether there are large particle protrusions under a microscope.
- Observe the surface of the bladeedge whether there are objects( such as residue or metal) under a high-power microscope.
In addition to the factors of the grinding wheel itself, there are other factors that can affect the result of roughness:
3. Other Chipping in Wafer Saw
There are three main reasons for abnormal chipping during the cutting process.
- The workpiece has displacement and deformation
- Feed rate and cutting depth
- High speed blade deflection
Solution:
- Increase the baking temperature and time after applying the film, and replace the substrate material
- Adjust appropriate processing parameters based on the material of the workpiece
- Aspectequipment spindle accuracy and blade dynamic balance accuracy
Back Chipping in Wafer Saw
There Are Three Main Directions For Investigation For Back Chipping.
- Diamond dicing blade
- Workpiece/fixed adhesive film
- Processing parameters
Five Correlation Factors Of Blade Related To Wafer Back Chipping
- The back chipping size of the blade before pre cutting is larger than that after pre cutting.
- The larger the diamond particles of the blade, the smaller the size of the back chipping .
- The lower the concentration of blade abrasive, the smaller the size of the back chipping.
- The softer the blade bonding agent, the smaller the size of back chipping.For example, the edge chipping of a resin diamond dicing blade is less than that of a metal bond blade.
- The thinner the blade, the smaller the size of back chipping.
Solution:
- Dress the blade with dressing board and perform pre cutting.
- Choose a suitable blade for cutting off (recommended 3000-3500 mesh).
- Choose a blade with low concentration for cutting off(recommended 50-70).
- Choose a blade with softer bond formula for cutting off.
- Choose a thinner bladefor cutting off.
There Are Three Factors Of Consumable Materials Related To Wafer Back Chipping.
- Fixing method (paraffin, adhesive film, fixture)
- Fixed force.
- Fixed auxiliary materials (adhesive layer thickness, substrate thickness, substrate hardness).
Solution:
- For wafer cutting, choose blue film or UV film with strong adhesion, thin adhesive layer, and low substrate elasticity.
- Keep the ceramic pores on the surface of the cutting disc unobstructed, ensure even vacuum suction, and keep the working disc flat.
Four Correlation Factors Of Processing Parameters Related To Wafer Back Chipping
- Spindle speed. If the spindle speed is too high, the amount of work done by each abrasive particle will decrease, but the self sharpening ability of the blade will be suppressed, which may lead to passivation.
- Feed rate. If the feed rate is too high, it will increase the load on the blade, and the stress generated by the workpiece will also be large, which causesto back
- Cutting depth: If the cutting depth is too deep and the blade load is high, there may be a risk of blade breakage, which can cause the product to back chipping.
- Cooling water: If the cooling water pressure is too high, the blades will bedeformation. If the cooling water pressure is too low, the cooling effect is poor and the product surfacewill be contamination.
Solutiont:
1. Recommended spindle speed of 22-35k.
2. Set a reasonable feed rate.
3. Choose the appropriate amount of blade exposure.
4. Control the cooling water pressure.
Dicing Blade Collection
The dicing process involves many objects, all of which are difficult to cut material with different parameter properties. There are metal bond dicing blade( bronze and electroplated) and resin bond dicing blade, and also hub and hubless dicing blade. Cutting different materials is basically chosen based on experience. For example, electroplated diamond dicing blade are the first choice for wafer cutting.For the dicing issue with dicing blade, contact us and we will forward to our engineers and response timely.
