摘要:
Plural shot areas arranged in succession in a two-dimensional array on a substrate are aligned to a predetermined reference position in a fixed coordinate system. At least three of the plural shot areas are selected as specified shot areas. Coordinate values (positions) of alignment marks associated, respectively, with the specified shot areas are measured. Anticipated coordinate values are calculated from preset coordinate values, based on an array model of the shot areas, predetermined by a first equation. A unique relation defined by a second equation is assumed, between the anticipated coordinate values and actual coordinate values in the alignment. Parameters of the relation are determined so as to minimize the average error between the measured coordinate values and coordinate values calculated from the relation. Actual coordinate values of the shot areas on the substrate are calculated based on the parameters and the anticipated coordinate values.
摘要:
The relative positions of an alignment mark on a wafer and index marks on an index plate within an optical system are detected by image processing. The index marks are illuminated by an illuminating light which is independent of an illuminating light for the wafer mark. An image of the wafer mark by a return light from the wafer and images of the index marks by the independent illuminating light are simultaneously picked up by a CCD image pickup device and the position of the first mark is detected from a combined image of these images by image processing.
摘要:
A position detecting apparatus is used with an exposure apparatus for projecting a mask pattern onto a substrate. The position detecting apparatus detects a position of an alignment mark formed on the substrate by sending light through a film having a wavelength-selective feature. The position detecting apparatus comprises a light sending system for emitting the position detecting light, a wavelength changing means for adjusting a wavelength band of the position detecting light directed onto the alignment mark, on the basis of the wavelength transmittance of the film having the wavelength-selective feature, and a light receiving system for detecting the light from the alignment mark. The position of the alignment mark can be determined on the basis of a photoelectric conversion signal outputted from the light receiving system.
摘要:
Two laser beams with a frequency difference are applied to a wafer mark on a wafer from an LIA (Laser Interferometric Alignment) system through a projection optical system, and diffracted light beams generated from the wafer mark are received by first to third light-receiving devices, respectively, in the LIA. The first light-receiving device receives first interference light comprising .+-.1st-order diffracted light beams (first processing mode). The second and third light-receiving devices respectively receive second and third interference lights comprising zeroth-order light and 2nd-order diffracted light (second processing mode). Alignment is effected by using either of the two processing modes which gives better measurement reproducibility.
摘要:
In the case where the previous process (X) and the previous process (Y) are different in step 310, only a distortion amount in an X-axis direction is extracted from image distortion data of the previous process (X) in Step 316 and only a distortion amount in a Y-axis direction is extracted from image distortion data of the previous process (Y) in Step 318, and then in Step 320, image distortion data is created by synthesizing the extracted distortion amounts, and the synthesized image distortion data is used for subsequent adjustment of projected images. With this operation, the distortion of projected images can be adjusted per axis and accordingly overlay exposure with high accuracy can be realized.
摘要:
A projection exposure apparatus according to the present invention comprises a projection optical system for projecting a pattern of a mask onto each of exposure areas on a photosensitive substrate, and a mark detection system of off-axis type spaced apart from the projection optical system by a predetermined distance. According to one aspect of the present invention, the projection exposure apparatus includes a calculating means for determining an offset amount of an imaging position of the projection optical system and an offset amount of a best focus position of the mark detection system of off-axis type on the basis of the amount of change of an environmental condition to which the projection optical system and the mark detection system are subjected. The detection of a positioning mark on the substrate is performed after a surface of the substrate at a position of the mark detection system is aligned with the best focus position, in consideration of the offset amounts. According to another aspect of the present invention, the projection exposure apparatus includes an inclination amount measuring means for determining an inclination amount of the surface of the substrate. The detection of the positioning mark on the substrate is performed after the inclination is eliminated or after the surface of the substrate at the position of the mark detection system is aligned with the best focus position in consideration of the inclination amount.
摘要:
A method of transferring a pattern of a mask onto shot areas on a substrate determines two sets of parameters in a single model equation. The parameters in one of the two sets relate to arrangement of a plurality of shot areas on the substrate, and the parameters in the other set relate to the shot areas per se. The mask and the substrate are moved relatively in accordance with the determined parameters.
摘要:
In the exposure method and apparatus, the distortion data of the projection lens in each exposure unit itself has already been known for each exposure unit. Accordingly, when the exposure unit which formed the alignment target layer has already been known, the known data of this exposure unit is used to correct at least one of the projection magnification and shot rotation determined according to multipoint EGA operation, and the exposure apparatus is adjusted by the amount of this correction. When the exposure unit forming the alignment target layer is unknown, the alignment mark exposure unit is specified from the state of distribution of non-linear error computed from the alignment mark measured values within a shot. Under thus determined correct projection magnification and shot rotation, a shot area is accurately overlaid with and exposed to a reticle pattern.
摘要:
Disclosed is an exposure method for exposing an image of a pattern formed on a mask to plural layers superimposed upon a substrate, comprising: the step of storing an alignment error between the plural layers together with at least one of exposure data and alignment data; the step of setting alignment data upon exposing another pattern to the substrate on the basis of at least one of the exposure data and alignment data; and the step of displacing the mask and the substrate relative to each other on the basis of the alignment data set in the previous step. There is further disclosed an exposure apparatus for exposing an image of a pattern formed on a mask to plural layers superimposed upon a substrate, comprising a storage for storing alignment errors between the plural exposure layers together with at least one of exposure data and alignment data; and a control unit connected to the storage for setting alignment data upon exposing another pattern to the substrate on the basis of at least one of the exposure data and alignment data; wherein the control unit controls the mask and the substrate so as to be displaced relative to each other on the basis of the alignment data set.
摘要:
At Step 602, the grid of a wafer loaded into an exposure apparatus is approximated by a mathematical function fitting up to, for example, a cubic function, and at Step 612, the magnitude of a residual error between the position of a sample shot area obtained by the function and an actually measured position is compared with a predetermined threshold value. GCM measurement is performed in a mathematical function mode in a subroutine 616, or it is performed in a map mode in a subroutine 616, on the basis of the result of the comparison. In addition, it is determined whether to extract non-linear components from the wafer in each lot on the basis of a variation in the temperature of the wafer (Step 622) and a variation in random error between the wafers (Step 624).