摘要:
A patterned dielectric layer is evaluated by measuring reflectance of a region which has openings. A heating beam may be chosen for having reflectance from an underlying conductive layer that is several times greater than absorptance, to provide a heightened sensitivity to presence of residue and/or changes in dimension of the openings. Reflectance may be measured by illuminating the region with a heating beam modulated at a preset frequency, and measuring power of a probe beam that reflects from the region at the preset frequency. Openings of many embodiments have sub-wavelength dimensions (i.e. smaller than the wavelength of the heating beam). The underlying conductive layer may be patterned into links of length smaller than the diameter of heating beam, so that the links float to a temperature higher than a corresponding temperature attained by a continuous trace that transfers heat away from the illuminated region by conduction.
摘要:
Heat is applied to a conductive structure that includes one or more vias, and the temperature at or near the point of heat application is measured. The measured temperature indicates the integrity or the defectiveness of various features (e.g. vias and/or traces) in the conductive structure, near the point of heat application. Specifically, a higher temperature measurement (as compared to a measurement in a reference structure) indicates a reduced heat transfer from the point of heat application, and therefore indicates a defect. The reference structure can be in the same die as the conductive structure (e.g. to provide a baseline) or outside the die but in the same wafer (e.g. in a test structure) or outside the wafer (e.g. in a reference wafer), depending on the embodiment.
摘要:
A structure having a number of traces passing through a region is evaluated by using a beam of electromagnetic radiation to illuminate the region, and generating an electrical signal that indicates an attribute of a portion (also called “reflected portion”) of the beam reflected from the region. The just-described acts of “illuminating” and “generating” are repeated in another region, followed by a comparison of the generated signals to identify variation of a property between the two regions. Such measurements can identify variations in material properties (or dimensions) between different regions in a single semiconductor wafer of the type used in fabrication of integrated circuit dice, or even between multiple such wafers. In one embodiment, the traces are each substantially parallel to and adjacent to the other, and the beam has wavelength greater than or equal to a pitch between at least two of the traces. In one implementation the beam is polarized, and can be used in several ways, including, e.g., orienting the beam so that the beam is polarized in a direction parallel to, perpendicular to, or at 45° to the traces. Energy polarized parallel to the traces is reflected by the traces, whereas energy polarized perpendicular to the traces passes between the traces and is reflected from underneath the traces. Measurements of the reflected light provide an indication of changes in properties of a wafer during a fabrication process.
摘要:
A method of fabricating a wafer includes forming a portion of the wafer, making a first measurement in the wafer using a first process, making a second measurement in the wafer using a second process each time the first measurement is made, using one of the first measurement and the second measurement to calibrate the other of the first measurement and the second measurement, and changing a process control parameter used in forming the portion of the wafer depending on the first measurement and on the second measurement.
摘要:
A sidewall or other feature in a semiconductor wafer is evaluated by illuminating the wafer with at least one beam of electromagnetic radiation, and measuring intensity of a portion of the beam reflected by the wafer. Change in reflectance between measurements provides a measure of a property of the feature. The change may be either a decrease in reflectance or an increase in reflectance, depending on the embodiment. A single beam may be used if it is polarized in a direction substantially perpendicular to a longitudinal direction of the sidewall. A portion of the energy of the beam is absorbed by the sidewall, thereby to cause a decrease in reflectance when compared to reflectance by a flat region. Alternatively, two beams may be used, of which a first beam applies heat to the feature itself or to a region adjacent to the feature, and a second beam is used to measure an increase in reflectance caused by an elevation in temperature due to heat transfer through the feature. The elevation in temperature that is measured can be either of the feature itself, or of a region adjacent to the feature.
摘要:
Embodiments of the invention contemplate the formation of a high efficiency solar cell using a novel plasma oxidation process to form a passivation film stack on a surface of a solar cell substrate. In one embodiment, the methods include providing a substrate having a first type of doping atom on a back surface of the substrate and a second type of doping atom on a front surface of the substrate, plasma oxidizing the back surface of the substrate to form an oxidation layer thereon, and forming a silicon nitride layer on the oxidation layer.
摘要:
A simplified manufacturing process and the resultant bifacial solar cell (BSC) are provided, the simplified manufacturing process reducing manufacturing costs. The BSC includes a back surface contact grid and an overlaid blanket metal reflector. A doped amorphous silicon layer is interposed between the contact grid and the blanket layer.
摘要:
Embodiments of the invention generally contemplate methods for treating a semiconductor solar cell substrate to reduce the number of undesirable material defects or interface state traps on the surface or within the substrate. These defects can adversely affect the efficiency of the solar cell because electron-hole pairs tend to recombine with the defects and are essentially lost without generating any useful electrical current. In one aspect, a method of forming a solar cell on a semiconductor substrate is provided, comprising doping a front surface of the substrate, applying a passivating layer to the front surface and/or a back surface of the substrate, and annealing the substrate to reduce the interface state trap density (Dit).
摘要:
In a thin-film photovoltaic (TF PV) module, stacked cells provide efficient conversion of solar energy without being afflicted by conventional problems such as current matching between layers. According to one aspect, the module includes separate terminals for the respective layers in the stack, thus allowing the current in each layer to be different without sacrificing efficiencies gained due to their different bandgaps. According to another aspect of the invention, a processing method according to the invention includes forming interconnects for each layer using etch and deposition processing, including forming separate interconnects for each respective layer, which interconnects can be coupled to respective sets of terminals.
摘要:
A method and apparatus measure properties of two layers of a damascene structure (e.g. a silicon wafer during fabrication), and use the two measurements to identify a location as having voids. One of the two measurements is of resistance per unit length. The two measurements may be used in any manner, e.g. compared to one another, and voids are deemed to be present when the two measurements diverge from each other. In response to the detection of voids, a process parameter used in fabrication of the damascene structure may be changed, to reduce or eliminate voids in to-be-formed structures.