1、 Material surface pretreatment
Cleaning treatment
Thoroughly cleaning the semiconductor chip and the substrate surface bonded to it is a fundamental and critical step. Organic solvent wiping, plasma cleaning, and other methods can be used to remove impurities such as oil stains, dust, and oxide layers on the surface. For example, wiping the surface with organic solvents such as acetone and isopropanol, and then treating it with plasma for a short period of time can effectively activate the surface, allowing polysilazane to better contact and form chemical bonds, thereby enhancing the bonding strength.
surface roughening
By appropriately increasing the roughness of the chip and substrate surfaces through physical or chemical methods, the contact area of the bond can be increased. Physical methods such as sandpaper polishing, sandblasting treatment, etc. (attention should be paid to controlling the strength and particle size to avoid damage to the chip); Chemical methods can use specific etching solutions to micro etch the surface, forming microscopic concave convex structures that allow for better embedding of polysilazane after curing, improving the mechanical bite force of the bond and thereby enhancing the bond strength.
2、 Optimize the formula of polysilazane
Add coupling agent
Choose appropriate coupling agents to add to polysilazane, such as silane coupling agents. One end of silane coupling agent molecules can undergo chemical reactions with silicon elements in polysilazane, while the other end can form chemical bonds with active groups such as hydroxyl groups and metals on the surface of chips or substrates, serving as a "bridge" to effectively enhance the bonding strength between polysilazane and the bonding interface. Common products such as gamma aminopropyltriethoxysilane can achieve good results in many semiconductor packaging applications.
Adjust the type and content of fillers
Add some functional fillers, such as inorganic fillers like nano silica and alumina. These fillers can improve the mechanical properties of polysilazane, and some active groups on the surface of the fillers can also participate in the bonding process, increasing the strength of the bond. Meanwhile, it is also important to control the content of fillers reasonably. A low content may not have a significant strengthening effect, while a high content may affect the flowability and coating uniformity of polysilazane, which is not conducive to bonding. Generally, multiple experiments are needed to determine the optimal filler content range.
3、 Control the curing process
cure temperature
Accurately control the curing temperature of polysilazane, and different polysilazane systems have their suitable curing temperature ranges. If the curing temperature is too low, the polysilazane may not be fully crosslinked and cured, resulting in insufficient bonding strength; If the temperature is too high, it may cause material decomposition, internal stress and other problems, affecting the bonding effect. For example, for certain thermosetting polysilazanes, the appropriate curing temperature may be between 100 ℃ -150 ℃. Gradually increasing the temperature within this temperature range and maintaining it for a certain period of time can help them fully cure and form high-strength bonds.
Curing Time
Ensuring sufficient curing time is also crucial, as the crosslinking reaction of polysilazane should be fully carried out to form a stable network structure between molecular chains, in order to achieve optimal bonding performance. The curing time is usually related to factors such as curing temperature and thickness of polysilazane, and needs to be reasonably set according to specific packaging processes and material characteristics. Generally, the optimal curing time is determined through methods such as thermal analysis.
Selection of curing method
In addition to common thermal curing, other curing methods such as light curing, moisture curing, or composite curing can also be considered. For example, for some temperature sensitive semiconductor devices, photo cured polysilazane can be rapidly cured at lower temperatures, reducing the impact of thermal stress on bonding while ensuring high bonding strength. Moreover, photo curing can achieve precise local curing, which has unique advantages in some special packaging structures.
4、 Optimize packaging process parameters
coating process
Adopting appropriate coating methods to ensure uniform distribution of polysilazane on the surface of chips and substrates, such as spin coating, spray coating, screen printing, etc., each has its own characteristics. Spin coating can obtain thin and uniform film layers, which is suitable for situations where high thickness accuracy is required; Spraying can be used for large-area coating, etc. Uniform coating can avoid stress concentration caused by local thickness differences, making the bonding more uniform and firm, and improving the overall bonding strength.
Apply pressure
During the curing process of polysilazane, applying a certain amount of pressure appropriately can help to expel air, bubbles, etc. at the bonding interface, enabling the polysilazane to adhere more tightly to the surface of the chip and substrate, enhancing intermolecular interactions, and improving bonding strength. The magnitude and duration of pressure should be adjusted reasonably according to the specific packaging structure and material characteristics to avoid damage to chips caused by excessive pressure.
Through comprehensive optimization of the above aspects, the bonding strength of polysilazane in semiconductor packaging can be effectively improved, meeting the requirements of semiconductor devices for packaging reliability.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150K.       
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.