The process of encapsulation requires a systematic preparation as a prerequisite. Preparation is mainly focused on application based material selection, material management and material conditioning. The preparation is carried out in the following four stages.
DesignThe first stage of preparation is a detailed assessment of the intended application of the die and package or PCB board. Their operational conditions in terms of temperature, chemical exposure and mechanical stability are considered. The tolerances of the individual components and the whole system is considered to determine the maximum temperature, chemical exposure limits and suitable processing environment. The physical size of the die and package/PCB is acquired to evaluate the encapsulation requirements. Some applications may require the encapsulation process to be simulated before it is carried out.
The second stage is to shortlist encapsulants which are compatible with the die, electrical interconnections and package/ PCB. The material selection takes in to consideration the main purpose of the encapsulation in conjunction with the operational conditions and tolerances of the die and package/PCB. They are often determined by the application requirements of the electronics to be encapsulated.
Material ManagementOnce a material is selected, it requires appropriate storage and transport arrangements to avoid any potential damage to its physical and chemical properties. Some materials have very specific requirements for storage and transport such as low temperatures and UV sensitivity. Encapsulants have different pot lives which is the maximum amount of time they can be stored; an encapsulant should not be used after the expiry of its pot life.
Material ConditioningMaterial conditioning deals with immediate preparation of the encapsulants for dispensing. This preparation is specific to material composition and requirements.
The advanced packaging facility has a range of material preparation and storage facilities. It has access to a dedicated material preparation facility which has a wide range of relevant equipment such as viscometers, speed mixer (centrifuge), vacuum chamber and mass scales. The materials preparation facility is located close to the packaging facility which helps avoid any significant time delay.
In terms of storage the packaging facility has a freezer which can store the materials down to -40°C and chemical cabinets which can store the materials at room temperature; the chemical cabinets are opaque so they offer protection against UV light. The facility also holds UV blocking containers for UV sensitive materials.The packaging facility has access to a range of finite element analysis software such as Autodesk, ANSYS and COMSOL. We also have the relevant expertise to be able to comprehensively analyse a die to be encapsulated.