This is the main reason why the chip coating is lost, so several suggestions are given.
Coating Adhesive for Semiconductor Chip
1. Attention should be paid to controlling the glue flow rate of dispensing valve. According to the technical summary, in order to ensure enough glue bonding parts and prevent excessive glue impregnating pad, the diameter of the glue spot should be half of the distance between the pads. The diameter of the glue spot after pasting should be 1.5 times of the diameter of the glue spot. The amount of dispensing depends on the rotating time of the screw pump, resulting in the chip glue dropping is related to the insufficient control of the glue. In fact, the rotating time of the pump should be selected according to the production conditions (including room temperature, glue viscosity and other factors).
Filling and gluing machine
2. The control of glue pressure and ambient temperature is also one of the reasons for chip coating loss. When the pressure is too high, it will easily lead to glue overflow and excessive glue. If the pressure is too low, there will be intermittent glue dispensing and leakage, resulting in defects. Operators should choose pressure according to the quality of the same glue and ambient temperature. Ambient temperature has a great impact on the glue viscosity, if the temperature is too low. When the temperature is too low, the adhesive point will become smaller and wire drawing will occur. The difference of 5 C in ambient temperature will lead to 50% change in the volume of the point colloid, and the chip coated parts may be related to this. Therefore, the environmental temperature adjustment should be controlled in time. At the same time, the environmental temperature should be guaranteed. For example, the adhesive point with low humidity is easy to dry, and the influence of adhesion is the problem of the coated parts.
331 control glue dispensing machine
3. Generally speaking, compared with the control of environmental temperature, the glue temperature is easy to be neglected, but in fact, both of them are also the causes of chip coating failure. Epoxy resin glue should be stored in the refrigerator at 0-5 C. It should be removed from the refrigerator half an hour before use, so that the glue fully meets the working temperature. The use temperature of glue is generally 23-25 C and then the flow control is carried out by using the dispensing valve. And the dispensing needle should be selected with appropriate specifications. If this temperature limit is reached, it can be well used for coating and avoid the problem of chip coating.