Research On The Influence Of Rheological Behavior Of Fluids To The Amount Of Fluid In A Time-Pressure Dispensing System

Time-pressure dispensing system has been widely used in Advanced Integrated Circuit Encapsulation (AICE) process. It is used to squeeze the adhesive fluid in a syringe onto boards or substrates with the pressurized air for wafer/substrate bonding. However, complexity of the process, which includes the air-fluid coupling and their nonlinear uncertainties, makes it difficult to obtain the desirable process model. The Non-Newtonian dispensing material (generally epoxy) only further deteriorates the case. Traditionally the dispensing process is based on the open-loop control, which heavily relies on the field engineer's experiences. Therefore, its performance is limited. For dispensing process, no systematic effort has been made and a desirable process model is not available. So, it is hard to make the quality of dots and lines consistent.Based on current application practice and aimed to the improve of making the quality of dots and lines consistent, this thesis research on the influence on consistent quality witch relation to rheological behavior of fluids in time-pressure dispensing technology by theoretic analysis, modeling, simulation and experiment. And then improve the quality of dispensing line through a new type of needle. Research the structure of needle in order to obtain the best effect to make the dispensing line uniformity.First, a survey of the AICE processes and the current fluid dispensing technology is first given. Then a comparative study of the fluid dispensing technology is made. The advantage and disadvantage of the different dispensing technology and their application area are presented. What's important, the structure of the system, the process of dispensing and the research evolving in time-pressure dispensing technology were introduced.Second, presents the rheological behavior of fluid and gives some experimental modal for the character. Base on the physical process, an nonlinear partial differential equation that describes the fluid motion has been given. By using the Spectral Method and a suitable basis function, an approximate fluid flow model for both the Newtonian and non-Newtonian fluid can be developed.Then, problems encountered frequently during dispensing were proposed, and the causes of such problems were explored. Some other factors influenced the quality of dispensing were also discussed. Some solutions about how to prevent those defects had also been given.Finally, introduce a new type of needle with a narrow slot in its tip which has utility. Analyze the influence on dispensing effect through the conclusion of experiment. Based on the conclusion of experiment, find the best size of slot.