摘要:

As the size of yield‐limiting particles has significantly decreased with the decrease in the feature size of leading‐edge ULSI devices, a clear need has arisen for a system capable of detecting particles of far below 50 nm in diameter on the surface of silicon wafers. If we employ a shorter wavelength (266 nm or below) laser for the laser‐scanning wafer inspection system, its sensitivity level can be raised to the range of 20 to 30 nm in diameter on smooth surfaces. However, so far, silicon surface morphology, such as crystal originated pits (COPs), micro‐scratches, microroughness, as well as residual chemical contamination on the surface of a mirror‐finished wafer, prevents the detector sensitivity from being raised to such a high level. Therefore, before further raising the particle detection sensitivity of the system, we must establish technologies for obtaining a super‐smooth silicon surface by employing scratch‐free precision surface polishing, COP‐free crystal growing/annealing, and microroughness/particle‐free wafer cleaning. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622481

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Ion implantation is one of the most critical processes in the front‐end‐of‐the‐line for ULSI technology. In the device defining process, a polysilicon gate is formed between the source and the drain of the transistors. After the poly gate formation, the silicon wafers are exposed to high dose implants such as source/drain and extension implants. These are usually done by batch implanters which host the wafers on a large wheel that spins at high RPM in vacuum during processing. Although some are worse than others, such implanters are known to generate particles leading to the damage of the poly gate. For instance, the high‐speed spin of the wafer wheel (1200 RPM) may provide strong enough force so that the impact of a small particle can be detrimental to a poly line structure. This destruction of the gate is classified as a missing‐poly defect. This work shows that implanter defectivity increases with the increase of wheel spin speed. Several other factors may also contribute to the missing poly issue, which includes wafer handling, damage from the plasma flood neutralization device and arcing from ion beam focusing elements near the wafer plane. This work presents the results of a systematic approach to characterize the defects in subsequent high dose implants. The defects are inspected on a KLA 2138 patterned wafer inspection tool, and the results are stored online for future references. The wafers are then placed on a JEOL 9855S SEM system so that the compositions of killer defects are examined by moving the probe to the exact location of defects. The combination of metrology tools enables us to determine how much defectivity is added to the product wafer and composition of the defects. From this we are able to categorize the defects and trace them to the originating sources based on the defect location and the composition. The data shows that the high‐speed spin of the wafer disc substantially increases the destruction of poly due to particles. Other effects of secondary importance, and the implanter effects on particle generation are also included in the paper. Possible preventative measures are discussed to eliminate or reduce this detrimental defect. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622482

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The timely identification of defects can lead to increased yields and significant cost savings in wafer production. X‐ray topography (XRT) is recognized as being a powerful tool for directly imaging defects in single crystals, such as semiconductor substrates and epitaxial thin‐films. In XRT, defects are imaged by measuring changes in the diffracted X‐ray intensity across a wafer due to strain and/or tilt that the defects introduce into the crystal lattice. We have developed a novel, high‐speed digital XRT method for non‐destructive defect characterization of up to 300mm diameter wafers. This method, called BedeScan™, offers substantial advantages to conventional topography, especially for rapid, convenient defect identification in a wafer manufacturing/processing environment. X‐rays from a microfocus source are diffracted from a wafer, which is translated with fast, high‐precision motions in front of a fixed CCD camera and a sequence of images is recorded. A virtual scan of the camera in the computer is undertaken to place each of these images at the correct position (x,y) in the final image. The final image contains impressions of defects across the full‐wafer,e.g.mechanical edge damage, misfit dislocations and slip bands. This method allows a limited area detector to be used to image specimens of any size. It is possible to record a low‐resolution full‐wafer topograph with subsequent high‐resolution, small‐area topographs in regions of special interest. BedeScan™ also offers the ability to measure only the periphery of a wafer for quick mechanical edge defect recognition. Quantitative maps of specimen distortion,e.g.wafer bowing as a result of thermal processing, can also be produced. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622483

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

As part of the semiconductor industry “contamination‐free manufacturing” effort, significant emphasis has been placed on reducing potential sources of contamination from process equipment and process equipment components. Process tools contain process chambers and components that are exposed to the process environment or process chemistry and in some cases are in direct contact with production wafers. Any contamination from these sources must be controlled or eliminated in order to maintain high process yields, device performance, and device reliability. This paper discusses new nondestructive analytical methods for quantitative measurement of the cleanliness of metal, quartz, polysilicon and ceramic components that are used in process equipment tools. The goal of these new procedures is to measure the effectiveness of cleaning procedures and to verify whether a tool component part is sufficiently clean for installation and subsequent routine use in the manufacturing line. These procedures provide a reliable “qualification method” for tool component certification and also provide a routine quality control method for reliable operation of cleaning facilities. Cost advantages to wafer manufacturing include higher yields due to improved process cleanliness and elimination of yield loss and downtime resulting from the installation of “bad” components in process tools. We also discuss a representative example of wafer contamination having been linked to a specific process tool component. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622484

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

In conventional semiconductor processes, gross photoresist scum has been detected with inspections using optical microscope or secondary electron microscope; trace molecular contamination or photoresist residue could be removed during wafer processes employing vigorous thermal, chemical, plasma or ion beam steps and thus had negligible effects on semiconductor manufacture. However, advanced semiconductor technology has become increasingly sensitive to molecular contamination that might be difficult to detect with traditional inspection and analysis techniques. Direct surface analysis by TOFSIMS provides sensitive detection of both elemental and molecular contamination that may be originated from environmental sources or from wafer fabrication processes. Monolayer level molecular contamination and very thin photoresist scum that were not detectable with conventional inspection techniques have been characterized with TOFSIMS in this paper. Detrimental effects of the very thin photoresist scum have been demonstrated with a 130 nm technology process. Cleaning process to remove molecular contamination was validated with TOFSIMS analysis. Detection of very thin photoresist scum can be accomplished with TOFSIMS imaging analysis. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622485

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The capabilities of a trace contamination analyzer are discussed and demonstrated. This analytical tool utilizes an electrospray, time‐of‐flight mass spectrometer (ES‐TOF‐MS) for fully automated on‐line monitoring of wafer cleaning solutions. The analyzer provides rich information on metallic, anionic, cationic, elemental, and organic species through its ability to provide harsh (elemental) and soft (molecular) ionization under both positive and negative modes. It is designed to meet semiconductor process control and yield management needs for the ever increasing complex new chemistries present in wafer fabrication. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622486

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The edge, bevel, and edge exclusion area of a wafer has historically been difficult to monitor for trace metals. Standard trace metal surface techniques such as total reflection x‐ray fluorescence spectroscopy, time‐of‐flight secondary ion mass spectrometry, and vapor phase decomposition inductively coupled plasma are currently not capable or have difficulty measuring metals to the edge and bevel of the wafer. With shared metrology toolsets and new materials being introduced into semiconductor fabs, it is important to measure possible contamination in these areas of the wafer. Tools that have edge grip pins or centering and aligning pins, also are at risk to contaminate wafers at the edge and bevel. A technique had been developed known as the beveled edge analysis tool that chemically extracts contamination from the edge, bevel and edge exclusion of a wafer that is then quantified by inductively coupled plasma mass spectrometry. In this study we will show correlation of this technique to standard trace element analysis methods. We will also present data from characterizing processes and fab tools that will benefit from this measurement. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622487

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A calibration facility has been developed to measure the peak diameter of particles suspended in liquid using differential mobility analysis (DMA). A description of the facility and the features that contribute to measurements with low uncertainties is included. Analysis of the DMA convolution integral allows correcting for the effects of charging probability, size distribution, and transfer function on the measured peak particle size. Current research using electrospray to aerosolize the particles is aimed at expanding the measurement size interval. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622488

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

X‐Ray Photoelectron Spectroscopy (XPS) is being used to an increasing extent for the characterization of new gate‐oxide materials, particularly for the determination of film composition, uniformity, and thickness. A key parameter for film‐thickness measurements by XPS is the effective attenuation length (EAL) for a particular material, photoelectron energy, and measurement configuration. Due to the effects of elastic scattering on signal‐electron trajectories, the EAL generally differs from the corresponding electron inelastic mean free path (IMFP) and is a function of film thickness and electron emission angle. We present calculations of EALs for four proposed gate‐oxide materials: zirconium dioxide, hafnium dioxide, zirconium silicate, and hafnium silicate. These EALs were obtained from the NIST Electron Effective‐Attenuation‐Length Database that uses an analytical expression derived from solution of the Boltzmann equation within the transport approximation. The EALs were computed for the relevant photoelectron lines excited by Al characteristic x rays and for a range of film thicknesses and emission angles of practical relevance. The EALs were compared with the corresponding IMFPs to determine the magnitudes of the correction for elastic‐scattering effects in each gate‐oxide material. For common measurement conditions, this correction varied between 12 &percent; and 20 &percent;. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622489

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The ellipsometric film thickness measurement precision for equivalent oxide thickness as prescribed by the International Technology Roadmap for Semiconductors is quite high. Although short‐term precision on a single ellipsometric instrument can be quite high, deviations of measured film thickness from instrument‐to‐instrument and from lab‐to‐lab for short‐term and long‐term periods of time need to be addressed. Since the derived film thickness is dependent on many factors, each one has to be dealt with in turn. These factors include: ellipsometric instrument precision and accuracy, consistency of film/substrate modeling, optical constants, regression analysis, and film surface contamination. Recommendations for standard models and optical constants are given along with the need to ensure high ellipsometric instrument precision and accuracy and controlled film surfaces and environmental conditions. In this study ultra‐thin refers to oxide films starting at 10 nm and being as thin as the native oxide. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1622490

出版商:AIP    

年代:1903

数据来源: AIP