Nikon Corporation

Masaharu Kawakubo

Ryoichi Kaneko

Nobutaka Magome

Kenji Nishi

Masahiko Yasuda

Osamu Furukawa

Hiroki Tateno

Kazuya Ota

Yuho Kanaya

Masahiko Okumura

Shinji Mizutani

Hiroki Okamoto

Takahisa Kikuchi

Chiaki Nakagawa

Masahiko Akizuki

In the case where the previous process (X) and the previous process (Y) are different in step, only a distortion amount in an X-axis direction is extracted from image distortion data of the previous process (X) in Stepand only a distortion amount in a Y-axis direction is extracted from image distortion data of the previous process (Y) in Step, and then in Step, 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.

Exposure method and lithography system

At Step, 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, 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, or it is performed in a map mode in a subroutine, 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) and a variation in random error between the wafers (Step).

Correction method and exposure apparatus

Positional information (an estimate value in which a linear component of positional deviation amount is corrected) of each shot on a wafer is calculated by a statistical computation using actual measurement values of positional information of a plurality of sample shots on the wafer (step). And, a variation amount of a non-linear component of positional deviation amount is calculated at predetermined intervals with respect to each of a plurality of measurement shots including the sample shots (step), and judgment is made about the necessity of update of correction information based on magnitude of the calculated variation amount of a non-linear component of each measurement shot area (step). Therefore, comparing with the case when actual values of positional information of all shots on the wafer are obtained at least once in each lot in order to update a correction value, the number of shots subject to positional information measurement and the measurement time can be reduced without fail.

Exposure method and device manufacturing method, exposure apparatus, and program

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.

Alignment method and apparatus therefor

An exposure method in which mask patterns are overlaid on one another on a substrate, which is an object to be exposed, by using a first and second exposure apparatuses having respective exposure fields of different sizes. The exposure method includes the steps of: sequentially transferring a first mask pattern onto the substrate in the form of a first array in units of a shot area of a predetermined size by using the first exposure apparatus; detecting at least either one of a perpendicularity error of the first array from a design value and a mean value of rotation angles of the shot areas in the first array when a second mask pattern is to be sequentially transferred onto the substrate. in the form of a second array in units of a shot area different in size from the unit shot area of a predetermined size by using the second exposure apparatus; and rotating the second mask pattern and the substrate relative to each other through an angle corresponding to a result of the detection, and thereafter, sequentially transferring the second mask pattern onto the substrate.

Exposure method for overlaying one mask pattern on another

An exposure method in which mask patterns are overlaid on one another on a substrate, which is an object to be exposed, by using a first and second exposure apparatuses having respective exposure fields of different sizes. The exposure method includes the steps of: sequentially transferring a first mask pattern onto the substrate in the form of a first array in units of a shot area of a predetermined size by using the first exposure apparatus; detecting at least either one of a perpendicularity error of the first array from a design value and a mean value of rotation angles of the shot areas in the first array when a second mask pattern is to be sequentially transferred onto the substrate in the form of a second array in units of a shot area different in size from the unit shot area of a predetermined size by using the second exposure apparatus; and rotating the second mask pattern and the substrate relative to each other through an angle corresponding to a result of the detection, and thereafter, sequentially transferring the second mask pattern onto the substrate.

Exposure methods for overlaying one mask pattern on another

A method of aligning each of a plurality of processing areas arranged on a substrate with a predetermined transfer position in a static coordinate system XY for defining a moving position of said substrate, a pattern of a mask being transferred to each of the plurality of processing areas, the method comprising the steps of: wherein each of the plurality of processing areas has a specific point and a plurality of marks for alignment arranged by a predetermined positional relationship with respect to said specific point; measuring coordinate positions of a predetermined number of marks selected from several processing areas of the plurality of processing areas on the static coordinate system XY; calculating a plurality of parameters in a model equation expressing the regularity of arrangement of the plurality of processing areas by performing a statistic calculation by use with the measured plurality of coordinate positions, arrangement coordinate values upon the design of the specific points of the several processing areas and relative arrangement coordinate values upon the design of the selected marks of the several processing areas with respect to corresponding the specific points on the several processing areas; and determining coordinate positions of respective said specific points of the plurality of processing areas on the static coordinate system XY by using the calculated parameters.

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.

Position detecting apparatus

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.

Exposure method and apparatus

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.

Apparatus for detecting a position of an optical mark

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 includes a light sending system for emitting the position detecting light, a wavelength changing device 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.

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.

Exposure method utilizing alignment of superimposed layers

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.

Alignment method for positioning a plurality of shot areas on a substrate

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.

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Kumagaya, Japan

Masaharu Kawakubo