Application of low temperature micro-solid nitrogen particles and its semiconductor wafer cleaning technology

introduction

In recent years, the high-functional high functionality of micrometer low-temperature solid particulates has been concerned in the field of ultra-high thermal flux cooling technology applied to high heat emission devices. In order to effectively utilize such low-temperature solid particles in advanced nanotechnology, our laboratory has developed a new physical semiconductor cleaning method, which uses a low temperature spray.

In the present method, in order to clarify the detailed mechanism of microscopic (SN2) particle behavior, a combined calculation of fluid kinetic analysis is carried out to clarify the micro-low temperature monolithic particulate heat transfer mechanism of the traditional measurement. For the expression of the control equation, the thermodynamic behavior of a single micro SN2 particle phase change is controlled by the Navier Stokes equation, the continuity equation, and the energy equation. The decisive feature of this phenomenon is to occur in strong evaporation (and later condensation) in the SN2 particles and the surrounding air phase interface. In addition to these thermodynamic analysis, the application of micro SN2 spray in semiconductor wafer cleaning technology was also studied. The SN2 particles impact silicon wafer heating machinery removal cleaning characteristics were clarified from the experimental and numerical values. Effects of ultra-high thermal flux cooling on removal properties of the heat shrink resist of organic materials were studied. In addition, the effect of ultrasonic atomizing micro-solid nitrogen on wafer ultra-clean performance.

experiment

For wafer samples used in the process, the peeling properties of the polysilicon / gate silicon oxide / silicon substrate coated with the positive KrF photoresist were examined. These wafers are manufactured as follows. First, a hot oxidation of 8 inch P-type silicon substrates and a 6-nanometer thick gate oxide layer is deposited on the substrate. A 150 nm thick polysilicon layer was deposited on the gate oxide using LPCVD (low pressure chemical vapor deposition). The HMDS (hexamethylene silicon) layer is applied to the surface of the polysilicon to help the photoresist adhere to the polysilicon, and then the rotary coater is used to form 500 nm thick photoresist layers on the HMDS layer. . Photoresist is patterned using 193 nm KrF excitation light. The door length is 0.34m, and the door width is 10m. Polysilicon is electrocardiated by an inductive coupled plasma etch system (silicon etch system, application material company) to form bromide / oxygen chemical etching into a pattern. These wafers are cut into a rectangular sheet of approximately 5 mm × 5 mm.

Results and discussion

Figure 7 shows the calculation results of the non-organized internal stress distribution of the SN2 particles and the deformed resist. It can be seen that the interaction between the SN2 particles and the resist is reasonably simulated. The size of the stress in the wafer resist increases as the plastic deformation increases. The pressure between the SN2 particles and the pressure of the wafer resist increases with the impact of the SN2 particles. It may be possible to predict the collision of SN2 particles and plastic deformation, and the collision causes the shear deformation of the resist – polysilicon interface. As a result, the resist removal performance is improved by the scratching effect of the micro-recess in the narrow recess between the wiring pattern.

Figure 7 Replace the calculation of the stress distribution of the reaction particles and deformation resists

Figure 8 shows an experimental result (scanning electron microscopy) using micro SN2 spray produced by the Lavar nozzle method (scanning electron microscopy). The resist can be effectively removed, and the main contaminants on the surface of the wafer are also successfully removed. This improved resist removal cleaning performance is a result of the removal of the motion resist removal of the very fine (nanoscale diameter dimension) SN2 particles. At the current stage of technological development, a given Sn2 particle digital density condition is a small amount of residual resist in the concave portion of the wiring pattern. However, we have successfully developed a single component of a single component that does not use gaseous helium.

Figure 8 Remove the experimental result of the photoresist with a micro SN2 spray (scanning electron microscope image)

Values ??and experiments have found that due to the ultra-high heat transfer characteristics, the mixed interaction of the fluid mechanical force and the thermal mechanical force contributes to the resist removal – the cleaning process. In particular, the effect of ultra-high thermal flux cooling on the resistance properties of thermal shrinkage removing resistance of the resist material was found, and the effect of ultrasonic atomized micro Sn2 particles on the ultra-clean performance of the semiconductor wafer was newly discovered.

Summarize

When the micro-solid nitrogen particles are used in the heated substrate together with the refrigerant, the ultra-high cooling heat flux level is achieved during operation, and therefore, the cooling performance is better than conventional liquid spray cooling. Since the micro SN2 cooling has the advantage of avoiding direct contact and latent heat transfer of the membrane boiling state, the ultra-short time scale heat transfer in the thin boundary layer is more likely to be in the liquid spray.

Numerical and experiments have found that the impact and ultra-high heat transfer characteristics of the micro-solid particles contribute to the resist removal – the cleaning process. An important discovery is that the impact of ultra-high thermal flux cooling plays an important role in removal properties related to thermal contraction of resistant materials.

The results obtained are of great significance in the field of low temperature cooling technology of advanced high heat emission devices, but will also help nano-devices engineering, which is closely related to semiconductor wafer cleaning technology.