摘要:
The present invention makes the use of measurement of a diffraction spectrum in or near an image plane in order to determine a property of an exposed substrate. In particular, the positive and negative first diffraction orders are separated or diverged, detected and their intensity measured to determine overlay (or other properties) of exposed layers on the substrate.
摘要:
The present invention makes the use of measurement of a diffraction spectrum in or near an image plane in order to determine a property of an exposed substrate. In particular, the positive and negative first diffraction orders are separated or diverged, detected and their intensity measured to determine overlay (or other properties) of exposed layers on the substrate.
摘要:
A scatterometer configured to measure a property of a substrate, includes a radiation source configured to provide a radiation beam; and a detector configured to detect a spectrum of the radiation beam reflected from a target (30) on the surface of the substrate (W) and to produce a measurement signal representative of the spectrum. The apparatus includes a beam shaper (51, 53) interposed in the radiation path between the radiation source and the detector, the beam shaper being configured to adjust the cross section of the beam dependent on the shape and/or size of the target.
摘要:
A scatterometer configured to measure a property of a substrate, includes a radiation source configured to provide a radiation beam; and a detector configured to detect a spectrum of the radiation beam reflected from a target (30) on the surface of the substrate (W) and to produce a measurement signal representative of the spectrum. The apparatus includes a beam shaper (51, 53) interposed in the radiation path between the radiation source and the detector, the beam shaper being configured to adjust the cross section of the beam dependent on the shape and/or size of the target.
摘要:
A method of determining an overlay error. Measuring an overlay target having process-induced asymmetry. Constructing a model of the target. Modifying the model, e.g., by moving one of the structures to compensate for the asymmetry. Calculating an asymmetry-induced overlay error using the modified model. Determining an overlay error in a production target by subtracting the asymmetry-induced overlay error from a measured overlay error. In one example, the model is modified by varying asymmetry p(n′), p(n″) and the calculating an asymmetry-induced overlay error is repeated for a plurality of scatterometer measurement recipes and the step of determining an overlay error in a production target uses the calculated asymmetry-induced overlay errors to select an optimum scatterometer measurement recipe used to measure the production target.
摘要:
An inspection apparatus measures a property of a substrate including a periodic structure. An illumination system provides a beam of radiation with an illumination profile including a plurality of illuminated portions. A radiation projector projects the beam of radiation onto the substrate. A detector detects radiation scattered from the periodic structure and separately detects first order diffracted radiation and at least one higher order of diffracted radiation of each of the illuminated portions. A processor determines the property of the substrate from the detected radiation. The plurality of illuminated portions are arranged such that first order diffracted radiation arising from one or more of the illuminated portions are not overlapped by zeroth order or first order diffracted radiation arising from any other of the illuminated portions. Furthermore, the plurality of illuminated portions are arranged such that first order diffracted radiation arising from the one or more of the illuminated portions are overlapped by at least one of the higher orders of diffracted radiation arising from any other of the illuminated portions.
摘要:
A method of determining an overlay error. Measuring an overlay target having process-induced asymmetry. Constructing a model of the target. Modifying the model, e.g., by moving one of the structures to compensate for the asymmetry. Calculating an asymmetry-induced overlay error using the modified model. Determining an overlay error in a production target by subtracting the asymmetry-induced overlay error from a measured overlay error. In one example, the model is modified by varying asymmetry p(n′), p(n″) and the calculating an asymmetry-induced overlay error is repeated for a plurality of scatterometer measurement recipes and the step of determining an overlay error in a production target uses the calculated asymmetry-induced overlay errors to select an optimum scatterometer measurement recipe used to measure the production target.
摘要:
An inspection apparatus measures a property of a substrate including a periodic structure. An illumination system provides a beam of radiation with an illumination profile including a plurality of illuminated portions. A radiation projector projects the beam of radiation onto the substrate. A detector detects radiation scattered from the periodic structure and separately detects first order diffracted radiation and at least one higher order of diffracted radiation of each of the illuminated portions. A processor determines the property of the substrate from the detected radiation. The plurality of illuminated portions are arranged such that first order diffracted radiation arising from one or more of the illuminated portions are not overlapped by zeroth order or first order diffracted radiation arising from any other of the illuminated portions. Furthermore, the plurality of illuminated portions are arranged such that first order diffracted radiation arising from the one or more of the illuminated portions are overlapped by at least one of the higher orders of diffracted radiation arising from any other of the illuminated portions.
摘要:
An apparatus measures properties, such as overlay error, of a substrate divided into a plurality of fields. The apparatus includes a radiation source configured to direct radiation onto a first target of each field of the substrate. Each first target (T4G) has at least a first grating and a second grating having respective predetermined offsets, the predetermined offset (+d) of the first grating being in a direction opposite the predetermined offset (−d) of the second grating. A detector is configured to detect the radiation reflected from each first target and to obtain an asymmetry value for each first target from the detected radiation. Further, a module is configured to determine an overlay value for each first target based on at least the obtained asymmetry value and the predetermined offsets and determine a polynomial fit across a plurality of first targets of a corresponding plurality of fields of the substrate for a relationship between the obtained asymmetry value and determined overlay value of each first target.
摘要:
A method and associated apparatus determine an overlay error on a substrate. A beam is projected onto three or more targets. Each target includes first and second overlapping patterns with predetermined overlay offsets on the substrate. The asymmetry of the radiation reflected from each target on the substrate is measured. The overlay error not resultant from the predetermined overlay offsets is determined. The function that enables calculation of overlay from asymmetry for other points on the wafer is determined by limiting the effect of linearity error when determining the overlay error from the function.