Papers by Keyword: Wafer Cleaning

Abstract: A study for uniform deposition on whole area of wafer was conducted to help check the uniformity of cleaning technology between wafer center to edge. A new method of particle deposition was devised different from the conventional studies using the center nozzle and electric field. Our deposition chamber features wafer rotating method and deposition by the principle of convection and diffusion. In this study, we focused on the effect of wafer rotation speed and rotation number to particle deposition result. After setting the optimum condition, fine results with well deposited shape on whole area of the wafer and outstanding particle size uniformity of more than 70% were obtained. Although particle size shift phenomenon occurred in the measurement result using SP5 due to the intrinsic principle, SEM analysis demonstrated that particles with 60, 80 nm sized silica particles were well deposited on wafer. We believe the standard wafer made by our particle deposition system could be utilized and helpful for performance evaluation and development of wafer cleaning technologies.

Abstract: The semiconductor industry is undergoing a transition driven by end use markets. In recent years, mobile devices have been the leading generator of growth. Now the connection of various products and machines to the internet is generating new and extensive demands for memory (storage of the data), logic (intelligent processing of the data including machine learning), and sensing (e.g., image sensors generating visual data). Thus the versatile planar MOS transistor based semiconductor technology has diverged into various specialized and complex branches, with each technology type using unique approaches to address scaling challenges. These lead to specific requirements for semiconductor wafer surface preparation. This paper will review the high level industry trends and how they affect surface preparation specifically.

Abstract: The cleaning process of the silicon wafer becomes one of the most important procedures in semiconductor fabrication. It is acknowledged to remove the contamination on the wafer surface as well as to promote an acceptable surface roughness, prior to performing various deposition methods. The wafer cleaning process which based on hot alkaline and acidic solutions is known as the RCA cleaning. The RCA is still the most important wafer cleaning method used in wafer fabrication industry. In this paper, the effects of various cleaning procedure to the silicon wafer surface roughness are measured using AFM. Subsequently, an optimum cleaning recipe is discussed and proposed.

Abstract: Emerging ultrasonic and megasonic cleaning demands in various applications (solar cell, storage devices, wafer and mask cleaning, etc.) dictate the need to understand the acoustic cavitation under different operating conditions to optimize efficiency of cleaning and reduce damage. Major parameters that affect cavitation include frequency of the sound field, operating power of the transducer and the cleaning chemistry. Previous studies have reported the use of common techniques such as multi-bubble sonoluminescence [1] and sono-electrochemistry [2] to understand acoustic cavitation. The disadvantage with sonoluminescence technique is that it characterizes cavitation mainly in the bulk of the solution, which may not be pertinent to wafer cleaning applications where the interest is in understanding cavitation phenomena close to the wafer surface. Although, sono-electrochemical techniques employing microelectrode are capable of measuring cavitation in the vicinity of a solid surface, they are limited to measurements on an extremely small area due to the miniscule size (5-25 μm) of the electrode. In this context, hydrophone measurements offer significant benefit as they can be taken near a solid surface as well as on a relative large area (1-2 mm diameter) of the pressure sensitive tip.

Abstract: High frequency (1 MHz, megasonic) acoustic enhanced cleaning is a well established method of removing surface particles in semiconductor manufacturing processes. There are two fundamental designs of megasonic batch cleaning systems, indirect and direct.

Abstract: In the early days of the microelectronics industry, it became clear that even trace contaminants could have detrimental impact on the electronic properties of fabricated devices. This realization led to the development of the so-called RCA clean for silicon surfaces [], which uses sequential baths in basic and acidic hydrogen peroxide solutions, now known as SCA-1 and SCA-2, to oxidize organic materials, remove particulates, and bind metallic impurities. The detailed characterization of this process as well as its simplicity and economic viability soon led to its widespread industrial adoption. Although the RCA clean includes an optional etch in dilute HF between the two cleaning solutions to remove the native oxide layer, the overall process results in an extremely clean but electronically defective oxide-terminated and thus extremely hydrophilic silicon surface, which we now know is quite rough on an atomic scale [].