Advanced Micro Devices Corporation

Advanced Micro Device, Inc.

John K Lowell

Tim Z Hossain

Fred N Hause

Robert Louis Dawson

Norman L Armour

Mohammed Anjum

Maung H Kyaw

Tony T Phan

Valerie A Wenner

Jerry I Dadap

Tom J Goodwin

Michael Downer

Julia Sherry

An improved sputter etching technique is provided for substantially preventing or reducing plasma etch damages associated with sputter etching. The plasma etch technique can utilize a semiconductor wafer having at least one diode formed within an inactive region of the wafer near the outer periphery of the wafer. The diode is capable of preventing charge transfer or arcing between the grounded anode and the p-channel gate region. By placing a diode within the inactive region of the wafer, problems such as gate oxide breakdown, threshold voltage skew, flat-band voltage skew, etc. can be minimized or substantially reduced. Alternatively, a standard wafer not having an implanted or diffused diode can be utilized to obtain similar beneficial results provided the sputter etch anode is retrofitted to include a diode placed between the anode and the ground terminal. Similar to the diode placed on the wafer, the retrofitted anode is used to provide a depletion region for preventing charge transfer therethrough.

Device for reducing plasma etch damage and method for manufacturing same

The present method provides for the detection and assessment of the net charge in a PECVD oxide layer deposited on a surface of a semiconductor substrate. Electrical potential differences across PECVD oxide layers on as-produced semiconductor substrates are measured. Resultant PECVD oxide charge derivative values are plotted on an control chart and compared to calculated control parameters. All measurement techniques are non-contact and non-destructive, allowing them to be performed on as-processed semiconductor substrates at any time during or following a wafer fabrication process. In a first embodiment, a contact potential difference V.sub.CPD between a vibrating electrode and the semiconductor substrate is measured while the semiconductor substrate beneath the vibrating electrode is subjected to a constant beam of high intensity illumination. The resultant value of V.sub.CPD is equal to the electrical potential difference across the PECVD oxide layer V.sub.OX (plus a constant). In a second embodiment, the semiconductor substrate is not illuminated curing the measurement of V.sub.CPD. A conventional SPV apparatus is used to measure the surface barrier potential V.sub.SP of the semiconductor substrate. Subtracting the measured value of V.sub.SP from the measured value of V.sub.CPD yields the value of V.sub.OX (plus a constant).

In-line detection and assessment of net charge in PECVD silicon dioxide

The present method provides for the detection and assessment of the net charge in a PECVD oxide layer deposited on a surface of a semiconductor substrate. Electrical potential differences across PECVD oxide layers on as-produced semiconductor substrates are measured. Resultant PECVD oxide charge derivative values are plotted on an control chart and compared to calculated control parameters. All measurement techniques are non-contact and non-destructive, allowing them to be performed on as-processed semiconductor substrates at any time during or following a wafer fabrication process. In a first embodiment, a contact potential difference V.sub.CPD between a vibrating electrode and the semiconductor substrate is measured while the semiconductor substrate beneath the vibrating electrode is subjected to a constant beam of high intensity illumination. The resultant value of V.sub.CPD is equal to the electrical potential difference across the PECVD oxide layer V.sub.OX (plus a constant). In a second embodiment, the semiconductor substrate is not illuminated during the measurement of V.sub.CPD. A conventional SPV apparatus is used to measure the surface barrier potential V.sub.SP of the semiconductor substrate. Subtracting the measured value of V.sub.SP from the measured value of V.sub.CPD yields the value of V.sub.OX (plus a constant).

A method of manufacturing a wafer having a buried oxide layer at a desired depth is disclosed. The method includes the steps of implanting a standard species ion at an energy at or above 1 MeV into an oxygen-rich wafer to form a defect region at the desired depth in the oxygen rich wafer. The wafer is annealed such that oxygen in the wafer is gettered to the defect region to form the buried oxide layer.

Method of forming buried oxygen layer using MeV ion implantation

Concentration measurement equipment is calibrated by performing a concentration measurement on a reference standard sample which includes a radioactive marker element. Because a count of decay products can be correlated with the number of atoms of the radioactive marker element, a precise count of decay products of the radioactive marker element is used to calculate an otherwise unknown number of atoms of the radioactive marker element on the reference standard sample. The calculated number of atoms of radioactive marker element is then used to calibrate a concentration measurement of the radioactive marker element by the concentration measurement device. Suitable radioactive marker elements for use in calibrating concentration measurement equipment include Pm-147 and Tc-99. Materials, methods and systems in accordance with the teachings of the invention are useful for calibrating concentration measurements and measurement equipment, including Total X-ray Fluorescence (TXRF) and Time Of Flight-Secondary Ion Mass Spectroscopy (TOF-SIMS) measurements and measurement equipment.

Ultra-low level standard for concentration measurements

The present method allows detection of heavy metal impurities introduced into a silicon wafer during an ion implantation procedure. The method is quick, non-destructive, and functions in the presence of extensive lattice damage created during ion implantation. A thermal treatment follows ion implantation to cause any heavy metal impurities to diffuse into near-surface regions adjacent to major surfaces. A major surface of the silicon wafer is subjected to a high-injection SPV frequency sweep procedure before and after the thermal treatment. During each high-injection SPV frequency sweep procedure, the major surface is subjected to a train of light pulses modulated at frequencies within a frequency range of interest spanning from a low frequency cutoff (about 280 Hz) to a high frequency cutoff (about 10 kHz). Surface charge values are derived from surface photovoltages measured at each modulation frequency. Ratios of surface charge values corresponding to endpoints of the frequency range of interest are used to gauge generation lifetimes before and after the thermal treatment. A decrease in generation lifetime following the thermal treatment indicates the introduction and subsequent diffusion of heavy metal contaminants into the near-surface region adjacent to the analyzed surface.

Method of detecting heavy metal impurities introduced into a silicon

A method and apparatus are presented which provide non-intrusive detection of atoms of light elements (atomic numbers 3-13) on a surface of a semiconductor substrate using X-ray fluorescence (XRF). The present technique may be economically performed routinely on manufactured products. The method includes producing a monochromatic X-ray beam comprising X-ray photons with energy levels operably chosen to cause only atoms of light elements to emit secondary X-ray photons. The monochromatic X-ray beam is then focused onto a circular exposed region on the surface of the semiconductor substrate, the circular exposed region having a diameter ranging from about 0.5 mm to about 10.0 mm. Secondary X-ray photons emitted by atoms of light elements in the exposed region on the surface of the semiconductor substrate are directed to at least one X-ray detector. Each X-ray detector is aligned to receive secondary X-ray photons from a single light element, and is illuminated for a predetermined amount of time. The number of secondary X-ray photons detected by an X-ray detector in a predetermined amount of time is directly proportional to the number of atoms of a corresponding light element on the surface of the semiconductor substrate. The apparatus includes a high-power X-ray source, a first collimator, a first multilayer crystal, a focusing capillary, a second collimator, a second multilayer crystal, and at least one X-ray detector.

Method and apparatus for the detection of light elements on the surface

A method and apparatus is presented which applies X-ray fluorescence spectrometry techniques to the problem of determining the elemental composition and thickness of multi-layer structures formed upon a semiconductor substrate. The resulting method and apparatus allows fast, accurate, non-contact, non-destructive, single-measurement determination of the compositions and thicknesses of each thin film on a surface of a measurement sample. Primary X-ray photons emitted by two radioisotopic X-ray sources following defined X-ray paths are incident upon a measurement sample. If the primary X-ray photons have sufficient energy, atoms in the exposed surface of the measurement sample will absorb the energies of the incident primary X-ray photons and emit secondary X-ray photons with characteristic energy levels. Secondary X-ray photons following paths within a defined detection space will reach a sensing face of a lithium-drifted silicon detector and will be detected and counted by a measurement system. The elemental composition of a thin film on an exposed surface of a measurement sample may be determined from the characteristic energy levels of the secondary X-ray photons emitted by the atoms in the thin film. The areas under all corresponding peaks in a graph of the number of secondary X-ray photons detected in predetermined energy ranges (i.e., counts) versus the predetermined energy ranges are directly proportional to the thickness of the thin film.

Method and apparatus for determining the thickness and elemental

The method and apparatus of the present invention provides a fast, efficient, non-contact, non-destructive means of characterizing surface and near-surface regions of a semiconductor substrate subjected to high-energy (MeV) ion implantation through interpretation of a graph of surface charge versus modulation frequency of incident monochromatic light. The near-surface region of a semiconductor substrate is defined to extend from just below the surface of the semiconductor substrate to a depth of 0.8 .mu.m. Similar to existing SPV/SCI techniques, a semiconductor substrate is radiated with high photon energy such that energy bands become almost flat at the surface of the semiconductor substrate. Surface photovoltages produced at different modulation frequencies of incident light pulses are measured and recorded. Resultant surface charges are derived from measured surface photovoltages, and a graph is made of surface charge versus the modulation frequency of incident light pulses. Structural and material defects affecting the characteristics of the surface and near-surface regions of the semiconductor substrate may then be diagnosed from the resulting graph.

Method and apparatus for passive optical characterization of

A non-destructive, non-intrusive characterization of angstrom-level roughness characteristics of subsurface interfaces is performed by applying femtosecond light pulses from a laser onto a surface, and analyzing the contents of the reflected pulses. After impinging on the surface being analyzed, the pulses pass through optical filters, which attenuate the fundamental and third harmonic frequencies of the pulses, but keep a substantial portion of the second harmonic. Analysis of the second harmonic signals provides rapid, non-contact, interface-specific characterization of the angstrom-level interfacial microroughness of the subsurface. For semiconductor devices, the second harmonic signals can be used to detect strain, contamination, and trapped charges in the Si/Si(O.sub.2) interface.

Characterization of an external silicon interface using optical second

A method and device is provided for determining defects within a single crystal substrate. The methodology includes a surface photovoltage (SPV) technique in which the magnitude of non-linearity is quantified and correlated to defects within the crystal lattice. The correlation factor is determined in a rapid and efficient manner using least square correlation methodology without having to determine diffusion length and incur difficulties associated therewith. Obtaining a quantifiable least square correlation factor allows the operator to quickly determine the amount of crystalline damage often encountered by, for example, ion implantation. In addition, the operator can determine the relative depth and position of defective crystalline layers within the substrate based upon demarcations between monotonically and non-monotonically aligned points plotted in a graph of reciprocal photovoltage versus reciprocal absorption coefficient.

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Round Rock, TX, United States of America

John K Lowell