JP2005197338A - Aligning method and treatment equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aligning method capable of shortening a time required for an aligning. <P>SOLUTION: A substrate to be treated, on which alignment marks for the aligning are formed at every unit region, is placed on a holding base. The substrate to be treated is moved on the basis of the designed coordinates of the unit regions to be treated so that the unit regions to be treated are arranged at the place of a treatment. The alignment marks in the unit regions to be treated are detected and the quantities of positional displacements are obtained at the place of the treatment, the substrate to be treated is aligned on the basis of the obtained quantities of the positional displacements and the unit regions are treated. The corresponding relationship of the positional information of the substrate to be treated, to which the quantities of the positional displacements obtained by detecting the alignment marks are added, and the designed coordinates of the unit regions is obtained. The corresponding relationship is applied to the designed coordinates of the unit regions to be treated, and the positional information surely moving the substrate to be treated is acquired. The substrate to be treated is moved on the basis of the positional information. The unit regions arranged at the place of the treatment are treated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an alignment method and an exposure apparatus, and more particularly to an alignment method applied to a method of moving a substrate to be processed by a step-and-repeat method and an exposure apparatus to which the alignment method is applied.

  Patent Document 1 listed below discloses an alignment method applied to the step-and-repeat method. Hereinafter, the method disclosed in Patent Document 1 will be briefly described.

  A plurality of unit regions (chips) are defined on the wafer. The positions of the alignment marks in a specific plurality of unit areas are detected. An error parameter is determined from the design position of the alignment mark from which the position has been detected and the actual position actually detected. An array map of unit areas is created from the error parameter and the design position of each unit area. In accordance with this arrangement map, exposure is performed while positioning by a step-and-repeat method.

Japanese Examined Patent Publication No. 4-47968

  In the method disclosed in Patent Document 1, the position of the unit area is not detected in a state where the unit area to be exposed is moved to the exposure position. For this reason, if the wafer is displaced or deformed after the arrangement map is determined, the alignment accuracy is lowered. Further, in order to ensure high alignment accuracy, extremely high positioning accuracy is required for the stage on which the wafer is moved.

  By adopting a die-by-die alignment method that performs position detection for each unit region, the above-described problem is solved. In the die-by-die alignment method, first, rough positioning of a unit region to be exposed is performed based on the design position coordinates of the unit region. Thereafter, an alignment mark in the unit area to be exposed is detected, and the amount of positional deviation is measured. If the measured displacement amount exceeds the allowable value, the wafer is aligned with high accuracy.

  In the die-by-die alignment method, if the amount of positional deviation after rough positioning is large, the moving distance of the stage at the time of high-precision alignment becomes long. For this reason, the time required for alignment becomes long.

  An object of the present invention is to provide an alignment method that can shorten the time required for alignment. Another object of the present invention is to provide an exposure apparatus to which this alignment method is applied.

  According to one aspect of the present invention, (a) a substrate to be processed in which a plurality of unit regions are defined on the surface, each of the unit regions being positioned in the substrate to be processed by design coordinates determined at the time of design. And (b) the alignment mark is formed, and a step of placing the substrate to be processed on which the alignment mark for alignment is formed in at least some of the unit areas. A step of moving the substrate to be processed based on the design coordinates of the unit area to be processed so that the unit area to be processed is arranged at the processing position; and (c) in the unit area to be processed at the processing position. The alignment mark is detected to obtain a positional deviation amount, the substrate to be processed is aligned based on the obtained positional deviation amount, and the unit area is processed, and (d) alignment is performed in the step c. And a step of obtaining a first correspondence relationship between the position information of the substrate to be processed and the design coordinates of the unit area in consideration of the amount of positional deviation obtained by detecting the mark. .

  By applying the first correspondence obtained in step d to the design coordinates of a unit area that has not been processed, the position information of the substrate to be processed for placing the unit area at the processing position is obtained. Can do. Since this positional information includes the amount of positional deviation when the already processed unit area is positioned, more accurate positioning can be performed.

  Taking the electron beam proximity exposure as an example, the alignment method according to the embodiment will be described.

  FIG. 1A is a plan view of a semiconductor wafer 11 that is an object of the alignment method according to the embodiment. A plurality of unit regions 50 arranged in a matrix are defined on the exposed surface of the wafer 11. An XYZ orthogonal coordinate system is defined in which the row direction is the X axis, the column direction is the Y axis, and the normal direction of the exposed surface is the Z axis. The shape of the unit region 50a included in the exposed surface of the wafer 11 is, for example, a square or a rectangle. Such a unit region 50a is referred to as a “complete unit region”. The unit region 50b that extends around the outer peripheral line of the wafer 11 has a shape obtained by cutting out a part of a square or a rectangle. Such a unit region 50b is referred to as an “incomplete unit region”. The unit area 50 is a unit in which exposure is performed, and exposure is performed by moving one unit area 50 to the exposure position of the exposure apparatus. The unit area 50 is usually called a “die”.

  At the time of designing, the position of each unit region 50 in the wafer 11, that is, the coordinates in the XY plane is determined. The coordinates determined at the time of design are called “design coordinates” of the unit area 50. The design coordinates are coordinates in the XY coordinate system defined on the surface of the wafer 11.

  In each unit region 50, a plurality of chip regions 51 are defined. One integrated circuit element is formed in one chip region 51. FIG. 1A shows a case where four chip regions 51 are defined in one complete unit region 50a. The incomplete unit region 50b includes 0 to 3 chip regions 51 depending on the size and shape thereof.

  FIG. 1B shows a plan view of a state in which one unit region 50a and a transfer region 12a of a mask arranged close to the wafer are overlaid, and a schematic view of an observation optical system for alignment. Two X alignment marks WX1, WX2 and two Y alignment marks WY1, WY2 are arranged in the complete unit region 50a. The X alignment marks WX1 and WX2 are usually arranged at different positions with respect to the X-axis direction and the Y-axis direction. The Y alignment marks WY1 and WY2 are also usually arranged at different positions with respect to the X-axis direction and the Y-axis direction.

  Alignment marks MX1, MX2, MY1, and MY2 corresponding to the alignment marks WX1, WX2, WY1, and WY2 on the wafer are formed in the mask transfer region 12a. The positions of these alignment marks are the X-axis direction, the Y-axis direction, the rotation direction in the XY plane, and the mask relative to the mask, which are calculated from the positional deviation between the alignment mark on the wafer and the alignment mark on the mask. It is preferable to arrange the wafer so that the error of the relative expansion / contraction amount of the wafer becomes small.

  The observation optical system 20X1 observes the alignment marks WX1 and MX1. Similarly, the observation optical system 20X2 observes the alignment marks WX2 and MX2, the observation optical system 20Y1 observes the alignment marks WY1 and MY1, and the observation optical system 20Y2 observes the alignment marks WY2 and MY2. The optical axes of the observation optical systems 20X1 and 20X2 are inclined in the Y-axis direction from the normal direction of the exposed surface. The optical axes of the observation optical systems 20Y1 and 20Y2 are inclined in the X-axis direction from the normal direction of the exposed surface.

  FIG. 2 shows a schematic view of an alignment apparatus according to the embodiment. The alignment apparatus according to the embodiment includes a wafer / mask holding unit 10, an observation optical system 20, and a control device 30.

  The wafer / mask holding unit 10 includes a wafer holding table 15, a mask holding table 16, and moving mechanisms 17 and 18. At the time of alignment, the wafer 11 is held on the upper surface of the wafer holding table 15 and the mask 12 is held on the lower surface of the mask holding table 16. The wafer 11 and the mask 12 are arranged substantially in parallel so that a certain gap (proximity gap) is formed between the exposed surface of the wafer 11 and the surface of the mask 12 on the wafer side. When performing electron beam proximity exposure, a stencil type mask 12 is used. A transfer pattern and an alignment mark are formed by an opening provided in the mask membrane.

The moving mechanism 17 is fixed to the reference base 1 and can move the wafer holder 15 so that the relative position of the wafer 11 and the mask 12 in the exposed surface changes. The moving mechanism 18 can move the wafer holder 15 so that the distance between the exposed surface of the wafer 11 and the mask surface of the mask 12 changes. When taking the X axis from the left to the right in the figure, the Y axis from the front surface to the back surface in the direction perpendicular to the paper surface, and the Z axis in the normal direction of the exposed surface, the moving mechanism 17 X-axis, Y-axis direction, to adjust the relative position around the rotational direction (theta _Z direction) of the Z-axis, the moving mechanism 18, the Z-axis direction, rotation about the X-axis and Y-axis (tilt) direction ( The relative position in the θ _X and θ _Y directions) is adjusted.

  The moving mechanism 17 includes a coarse movement stage and a fine movement stage arranged on the coarse movement stage. The position of the coarse movement stage is detected by a linear encoder, and the position accuracy is about 1 μm. The position of the fine movement stage with respect to the coarse movement stage is detected by, for example, a capacitance sensor, and the positional accuracy is several nm. The position of the fine movement stage with respect to the reference base 1 is detected by a laser interferometer.

  An electron beam 42 is emitted from the exposure beam source 43. The electron beam 42 is irradiated onto the wafer 11 through the mask 12.

  The observation optical system 20 includes an image detection device 21, a lens 22, a beam splitter 23, and an optical fiber 24. In FIG. 2, the observation optical system 20Y2 shown in FIG. 1B is shown as a representative. The other observation optical systems 20X1, 20X2, and 20Y1 have the same configuration as the observation optical system 20Y2. The optical axis 25 of the observation optical system 20 is arranged so as to be parallel to the XZ plane and oblique to the exposed surface.

  Illumination light radiated from the optical fiber 24 is reflected by the beam splitter 23 to form a light bundle along the optical axis 25, and enters the exposed surface through the lens 22 at an angle.

  When the alignment marks provided on the wafer 11 and the mask 12 have scattering points such as edges or vertices, illumination light is scattered at these scattering points. Of the scattered light, light incident on the lens 22 is converged by the lens 22, and a part of the light passes through the beam splitter 23 and forms an image on the light receiving surface 29 of the image detection device 21. The imaging magnification on the light receiving surface 29 is, for example, 60 to 100 times.

  Light receiving pixels are arranged in a matrix on the light receiving surface of the image detection device 21. Each pixel generates an image signal corresponding to the pixel in accordance with the intensity of light emitted to the pixel. This image signal is input to the control device 30. Note that image signals from the other observation optical systems 20X1, 20X2, and 20Y1 are also input to the control device 30.

  The control device 30 performs image processing to obtain relative position information regarding the Y-axis direction between the alignment mark of the mask 12 and the alignment mark of the wafer 11.

  FIG. 3A is a plan view showing the relative positional relationship between the alignment mark on the wafer and the alignment mark on the mask. Alignment marks 13A and 13B on each wafer are configured by arranging three rectangular patterns in the Y-axis direction and 14 in the X-axis direction in a matrix. The alignment marks 13A and 13B constitute one alignment mark WY2 shown in FIG. One alignment mark 14 on the mask is configured by arranging three similar rectangular patterns in the Y-axis direction and five in the X-axis direction in a matrix. The alignment mark 14 corresponds to the alignment mark MY2 shown in FIG. In the state where the alignment is completed, the alignment mark 14 on the mask is arranged approximately at the center between the alignment marks 13A and 13B on the wafer in the Y-axis direction.

FIG. 3B is a cross-sectional view taken along one-dot chain line B3-B3 in FIG. The alignment marks 13A and 13B on the wafer are formed by patterning, for example, a SiN film or a polysilicon film formed on the exposed surface. A resist film 11 </ b> R is formed on the exposed surface of the wafer 11. The alignment mark 14 on the mask is configured by an opening formed in a mask membrane made of, for example, SiC. FIG. 4 is a sketch of an image on the light receiving surface 29A or 29B by scattered light from the edge. The horizontal direction (v-axis direction) in FIG. 4 corresponds to the Y-axis direction in FIG. 3A, and the vertical direction (u-axis direction) corresponds to the X-axis direction in FIG. Images 40A and 40B due to scattered light from alignment marks 13A and 13B on the wafer appear apart in the v-axis direction, and image 41 due to scattered light from alignment mark 14 on the mask appears therebetween. The images 40A and 40B and the image 41 appear at different positions with respect to the u-axis direction. By detecting the positions of the images 40A, 40B and 41 in the v-axis direction, positional information in the Y-axis direction between the alignment marks 13A and 13B on the wafer and the alignment mark 14 on the mask shown in FIG. Can be obtained.

The four sets of alignment marks shown in FIG. 1 (B), X-axis direction, it is possible to obtain positional information in the Y-axis direction, and theta _Z direction, and the relative distortion information of the wafer relative to the mask. Hereinafter, such information will be described.

  The coordinates of the alignment mark WX1 are (X1x, X1y), the coordinates of the alignment mark WX2 are (X2x, X2y), the coordinates of the alignment mark WY1 are (Y1x, Y1y), and the coordinates of the alignment mark WY2 are (Y2x, Y2y). The displacement amount of the alignment marks WX1 and MX1 in the X-axis direction is dx1, the displacement amount of the alignment marks WX2 and MX2 in the X-axis direction is dx2, the displacement amount of the alignment marks WY1 and MY1 in the Y-axis direction is dy1, and the alignment mark The amount of deviation in the Y-axis direction between WY2 and MY2 is dy2. By detecting dx1, dx2, dy1, and dy2, the amount of deviation dx in the X-axis direction, the amount of deviation dy in the Y-axis direction, the amount of deviation dθ in the θz direction, and the relative expansion / contraction amount dm can be obtained.

With reference to FIG. 5, an alignment method according to the embodiment will be described. In this embodiment, a case where only the complete unit area 50a shown in FIG. 1A is exposed will be described. The coordinates obtained by measuring the position of the wafer holding table 15 on which the wafer is placed with a laser interferometer are defined as laser coordinates (lx, ly, lθ). Here, lx and ly are each an X and Y coordinates, Erushita shows theta _Z coordinates. The design coordinates of each unit area 50 defined on the wafer is (wx, wy). Further, the coordinates of the wafer holding table 15 obtained by the linear encoder of the coarse movement stage of the moving mechanism 17 and the capacitance sensor of the fine movement stage are set as encoder coordinates (ex, ey).

  Since the encoder coordinates are directly used for controlling the wafer holding table 15, it can be considered as “position coordinates of the wafer holding table”. The laser coordinates are actually obtained by detecting the position of the wafer holding table 15, but the relative position between the wafer holding table 15 and the wafer 11 held thereon is fixed. Therefore, it can be considered as “coordinates indicating the position of the wafer”.

  In step S <b> 1, the wafer to be exposed is placed on the wafer holder 15. Wafer position detection and leveling are performed using an observation optical system. As a result, the design coordinates (wx, wy) of the unit area defined on the wafer are associated with the encoder coordinates (ex, ey). That is, if design coordinates of a certain unit area are designated, the moving mechanism 17 can be driven to move the unit area to the exposure position. After the wafer 11 is placed on the wafer holder 15 and leveling is performed, the relative positions of the wafer 11, the wafer holder 15, and the fine movement stage of the moving mechanism 17 do not change. For this reason, detecting the position of the fine movement stage with the laser interferometer is substantially the same as detecting the position of the wafer 11 or the position of the wafer holder 15.

  In step S2, based on the design coordinates (wx, wy) of the unit area, the unit area 50 to be exposed is moved to just below the mask 12 (exposure position). More specifically, the encoder coordinates are obtained from the design coordinates (wx, wy), and the wafer holding table 15 is moved to the encoder coordinates (ex, ey). In this state, a laser interferometer that detects the position of the wafer holding table 15 is initialized. This movement of the wafer holder 15 is referred to as “alignment based on design coordinates”.

  Proceeding to step S3, the four observation optical systems 20X1, 20X2, 20Y1, and 20Y2 shown in FIG. 1B are used to observe the relative positions of the corresponding wafer and mask alignment marks. When the positional deviation exceeds the allowable value, high-precision alignment (die-by-die alignment) is performed by controlling the fine movement stage of the moving mechanism 17. In step S4, the unit region 50 arranged at the exposure position is exposed through the mask.

  Proceed to step S5. Hereinafter, the process of step S5 will be described. Laser coordinates (lx, ly, lθ) of the wafer holding table 15 after alignment based on the design coordinates in step S2, encoder coordinates (ex, ey), and positional deviation amount (dx, dy, dθ) and the design coordinates (wx, wy) of the unit region 50 arranged at the exposure position are stored in the control device 30. Even during exposure, the position of the alignment mark is detected at a constant cycle, for example, a 30 ms cycle. In this case, as the misregistration amount (dx, dy, dθ) that is actually stored, the misregistration amount immediately before exposure, the average value of misregistration amounts obtained within a certain period immediately before exposure, Any of a positional deviation amount, an average value of the positional deviation amounts obtained during exposure, an average value of the positional deviation amounts obtained immediately before and during exposure, and the like can be employed.

  Here, the subscripts x, y, and θ mean coordinates relating to the X-axis direction, the Y-axis direction, and the θz direction, respectively. A conversion matrix M for associating these coordinates is defined as follows.

上記換算行列Ｍの第１行目の要素を求めるためには、

In order to obtain the element of the first row of the conversion matrix M,

を、最小二乗法を用いて解けばよい。その一例として、下記の正規方程式を解く方法が挙げられる。

Can be solved using the method of least squares. One example is a method of solving the following normal equation.

ここで、ｎは、得られた座標データの数であり、１つの単位領域のダイバイダイアライメントが完了すると、１つの座標データが得られる。

Here, n is the number of obtained coordinate data, and one coordinate data is obtained when the die-by-die alignment of one unit region is completed.

  Proceeding to step S6, it is determined whether the conversion matrix M can be obtained from the number of obtained coordinate data. If the conversion matrix M cannot be obtained, the process returns to step S2, and alignment is performed based on the design coordinates of the unexposed unit area to be exposed next. When the conversion matrix M can be obtained from the number of obtained coordinate data, the process proceeds to step S7, and the conversion matrix M is acquired.

  An example of this determination method will be described. If the number of obtained coordinate data is smaller than the number of unknowns to be obtained (three in the formula (3)), the normal equation cannot be solved, and the determination result is “uncalculated”. When the number of obtained coordinate data is greater than or equal to the number of unknowns, the simultaneous equations of Equation (3) are solved using, for example, a singular value decomposition method. If an error occurs during the calculation, the determination result is “uncalculated”. If no error has occurred, a conversion matrix has been obtained. In step S7, this conversion matrix is acquired (stored).

  In step S5, the laser coordinates (lx, ly, lθ) and the encoder coordinates (ex, ey) of the wafer holding table 15 are stored, so that the laser coordinates (lx, ly, lθ) are encoded by the same method. A conversion matrix for converting to coordinates (ex, ey) is also acquired.

  In step S8, the conversion matrix M is applied to the design coordinates (wx, wy) of the unit area to be exposed next, and the conversion coordinates (rx, ry, rθ) to which the wafer holder 15 is to be moved are obtained. Specifically, the converted coordinates are calculated by the following formula.

  The conversion matrix M is obtained in consideration of the positional deviation amounts (dx, dy, dθ) as shown in the mathematical formula (1). For this reason, the converted coordinates (rx, ry, rθ) obtained by the equation (4) are considered to be highly accurate position information in which a deviation corresponding to the positional deviation amount of the unit area aligned in the past has already been corrected. .

  In step S9, the converted coordinates (rx, ry, rθ) are converted into encoder coordinates (ex, ey), and the moving mechanism 17 is driven to move the wafer holding table 15 to the encoder coordinates.

  The actual position of the unit area deviates from the position indicated by the design coordinates due to various factors. For example, factors such as misalignment during transfer of a pattern that has already been transferred and thermal expansion of the wafer can be cited. In this embodiment, in step S9, the wafer holder 15 is moved based on the converted coordinates calculated by applying the conversion matrix to the design coordinates instead of the design coordinates of the unit area. This conversion matrix M includes information on the relative expansion / contraction amount of the wafer and the shift of the coordinate axis between the design coordinates and the laser coordinates.

  Even if the position of the wafer holding table 15 is detected by a laser interferometer and the wafer holding table 15 is moved so that the laser coordinates (lx, ly, lθ) coincide with the converted coordinates (rx, ry, rθ). Good. Compared with the case where the wafer holding table 15 is moved using only the encoder coordinates (ex, ey), alignment with higher accuracy can be performed.

  In both cases where encoder coordinates are used and laser coordinates are used, alignment is performed based on the converted coordinates. This alignment is called “alignment based on converted coordinates”.

  In step S10, die-by-die alignment is performed. In step S9, since the alignment based on the converted coordinates is performed, a higher position accuracy can be expected as compared with the case where the alignment is performed based on the design coordinates. For this reason, the moving amount of the stage at the time of die-by-die alignment can be shortened. This makes it possible to shorten the alignment time.

  In step S11, exposure is performed. Proceeding to step S12, it is determined whether exposure of all unit areas has been completed. If there is an unexposed unit area, the process returns to step S8, and converted coordinates are calculated from the design coordinates of the unit area to be exposed next. Subsequently, steps S9 to S12 are executed.

  When all the unit areas have been exposed, the wafer is unloaded from the wafer holder 15.

  As described above, by adopting the method according to the embodiment, the distance for moving the wafer holder 15 in step S10 can be shortened, and the time required for alignment can be shortened. Thereby, the throughput can be improved.

  When die-by-die alignment is performed in step S10, position data including the position coordinates of the wafer holding table 15, position shift information, and design coordinates of the unit area is obtained. Based on this position data, the conversion matrix M acquired in step S7 may be corrected. By creating the conversion matrix M from a larger amount of position data, the position accuracy of the converted coordinates can be further increased.

  Moreover, in the said Example, the process of collecting the position data for calculating | requiring the conversion matrix M from step S2 to S5 is shared with an actual exposure process. For this reason, there is almost no decrease in throughput due to the collection of position data.

  When performing electron beam exposure (for example, electron beam proximity exposure disclosed in Japanese Patent No. 2951947), if the amount of positional deviation between the mask and the wafer is small, the positional deviation is compensated by deflecting the electron beam. be able to. In the above embodiment, since the alignment accuracy after alignment based on the converted coordinates in step S9 is high, the displacement may be compensated by deflecting the electron beam instead of the die-by-die alignment in step S10.

  You may perform the process from step S2 to S5 for calculating | requiring the conversion matrix M with respect to the several unit area | region which is not mutually adjacent. According to this method, a conversion matrix is obtained based on position data obtained from a relatively wide area in the wafer. For this reason, when the deviation from the design coordinates has a characteristic tendency in a part of the wafer, it is possible to reduce the influence of the characteristic tendency on the conversion matrix.

  In the above embodiment, the case where only the complete unit region 50a shown in FIG. 1A is exposed has been described. Next, a method for exposing the incomplete unit region 50b will be described. Since a complete chip region also exists in the incomplete unit region 50b, more chips can be cut out by exposing the incomplete unit region 50b. In the alignment by the design coordinates and the die-by-die alignment in steps S2 and S3 shown in FIG. 5, since the positional deviation information is necessary in the subsequent step S5, the complete unit region 50a is set as the exposure target region.

  The incomplete unit region 50b is aligned and exposed in the processes of steps S8 to S13. In the incomplete unit region 50b, some of the four alignment marks WX1, WX2, WY1, and WY2 shown in FIG. 1B are missing. For this reason, in step S12, complete die-by-die alignment cannot be performed. However, in step S11, since the wafer is aligned based on the converted coordinates, the amount of positional deviation is small compared to the case where alignment is performed based on the design coordinates. Therefore, for the incomplete unit region 50b, the die-by-die alignment step in step S12 may be omitted. Alternatively, only the observable alignment mark may be observed, and only the misalignment that can be detected from the observed misalignment amount of the alignment mark may be corrected.

  If it is considered that the alignment accuracy in the alignment based on the converted coordinates in step S11 is sufficiently high, the die-by-die alignment step in step S12 may be omitted even when the complete unit region 50a is processed.

  In the above embodiment, the correspondence relationship between the design coordinates of the unit area and the coordinates of the wafer holder 15 is approximated by a linear expression, but it may be approximated by a quadratic expression. When approximated by a quadratic expression, the following relational expression is used instead of the above-described mathematical expression (1).

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

  In the above embodiment, the electron beam proximity exposure has been described as an example. In addition, the above alignment method can be applied to X-ray exposure, ultraviolet exposure, and semiconductor wafer inspection.

It is a top view of the wafer used as the object of the alignment method by an Example. It is the top view of one unit area | region, a mask n transfer area | region, and the schematic of an observation optical system. It is the schematic of the electron beam exposure apparatus by an Example. It is a top view of the alignment mark formed on the nominal mask on a wafer. It is sectional drawing of a wafer and a mask. It is the figure which sketched the image of the alignment mark. It is a flowchart for demonstrating the alignment method by an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wafer / mask holding part 11 Semiconductor wafer 11R Resist film 12 Mask 13A, 13B, 14 Alignment mark 15 Wafer holding stand 16 Mask holding stand 17, 18 Moving mechanism 20 Optical system 20X1, 20X2, 20Y1, 20Y2 Observation optical system 21 Image detection Device 22 Lens 23 Beam splitter 24 Optical fiber 25 Optical axis 29 Light receiving surface 30 Control devices 40A, 40B, 41 Image 42 Electron beam 43 Exposure beam source 50 Unit area (die)
50a Complete unit area 50b Incomplete unit area 51 Chip areas WX1, WX2, WY1, WY2, MX1, MX2, MY1, MY2 Alignment marks

Claims (12)

(A) A substrate to be processed in which a plurality of unit regions are defined on the surface, and each of the unit regions has a position in the substrate to be processed defined by design coordinates determined at the time of design. Placing the substrate to be processed on which the alignment mark for alignment is formed in at least some of the plurality of unit regions on the holding table;
(B) moving the substrate to be processed based on the design coordinates of the unit region to be processed so that the unit region to be processed on which the alignment mark is formed is arranged at the processing position;
(C) At the processing position, an alignment mark in the unit region to be processed is detected to obtain a positional deviation amount, and the substrate to be processed is aligned based on the obtained positional deviation amount. A process of processing,
(D) obtaining a first correspondence relationship between the position information of the substrate to be processed and the design coordinates of the unit area in consideration of the amount of displacement obtained by detecting the alignment mark in the step c. Alignment method. After the step d,
(E) applying the first correspondence to design coordinates of a unit region to be processed next to obtain position information for moving the substrate to be processed;
(F) moving the substrate to be processed based on the position information obtained in the step e;
(G) The position alignment method of Claim 1 which has a process of processing to the unit area | region arrange | positioned at the process position at the said process f. Correlating the position coordinates of the holding table with the design coordinates of the unit area between the steps a and b;
In the step b, the position coordinate of the movement destination of the holding table is obtained from the design coordinates of the unit area to be processed, the holding table is moved to the position coordinate of the movement destination,
The first correspondence obtained in the step d indicates correspondence between position information obtained by adding the amount of positional deviation to coordinates indicating the position of the substrate to be processed and the design coordinates.
The position information obtained in the step e is position information of a substrate to be processed for arranging a unit area to be processed at a processing position.
The alignment method according to claim 2, wherein in the step f, the substrate to be processed is moved based on position information of the substrate to be processed obtained in the step e. Between step f and step g,
The alignment method according to claim 2, further comprising: (h) detecting an alignment mark in a unit region arranged at a processing position and aligning the substrate to be processed. 5. The position according to claim 4, further comprising a step of correcting the first correspondence relationship based on a positional deviation amount obtained by detecting an alignment mark in the step h and a design coordinate of the unit region. How to match. A mask on which a pattern to be transferred and an alignment mark for alignment are formed is disposed on the surface of the substrate to be processed placed on the holding table with a proximity gap therebetween, and the step c includes A step of detecting an alignment mark in a unit region arranged at a processing position and an alignment mark formed on the mask and aligning the two; and a unit region arranged at the processing position through the mask The alignment method according to claim 2, wherein the step g includes a step of exposing a unit region arranged at a processing position through the mask. A mask on which a pattern to be transferred and an alignment mark for alignment are formed is disposed on the surface of the substrate to be processed placed on the holding table with a proximity gap therebetween, and the steps c and g Includes a step of irradiating an electron beam through the mask to the unit region arranged at the processing position, and the step g detects an alignment mark in the unit region arranged at the processing position and calculates a positional deviation amount. The alignment method according to claim 2, further comprising a step of deflecting an electron beam to be irradiated so that the positional deviation is compensated based on the obtained positional deviation amount. The steps a to c are performed on a plurality of unit regions that are not adjacent to each other, and the first correspondence is obtained from information on the plurality of unit regions on which the processes of the steps a to c are performed in the step d. The alignment method according to claim 1, wherein a relationship is obtained. After the step d, for some of the unprocessed unit regions, the alignment is detected by detecting the alignment mark in the unit region arranged at the processing position in the step e, step f, and step f. Steps to compensate and Step g are executed, Steps e, Step f and Step g are executed for the remaining unit regions, and a step of compensating for misalignment between Steps f and g is executed. The alignment method according to claim 2 or 3, wherein: A holding table for holding a substrate to be processed having a surface to be processed and moving the substrate to be processed in a two-dimensional direction parallel to the surface to be processed;
An observation device for observing alignment marks on the substrate to be processed held on the holding table;
An observation result from the observation apparatus is input, and a control device that controls the wafer holder is provided.
(A) A substrate to be processed in which a plurality of unit regions are defined on the surface, and each of the unit regions has a position in the substrate to be processed defined by design coordinates determined at the time of design. Alignment marks for alignment are formed in at least some of the plurality of unit regions, and processing should be performed so that the unit region to be processed of the substrate to be processed placed on the holding table is disposed at the processing position. A step of moving the substrate to be processed based on the design coordinates of the unit area;
(B) At the processing position, an alignment mark in the unit area to be processed is detected to obtain a positional deviation amount, the substrate to be processed is aligned based on the obtained positional deviation amount, and the unit area is A process of processing,
(C) A step of obtaining a first correspondence relationship between the position information of the substrate to be processed and the design coordinates of the unit region in consideration of the positional deviation amount obtained by detecting the alignment mark in the step b. A processing device for controlling the holding table so as to be executed. The control device further includes, after the step c,
(D) applying the first correspondence to the design coordinates of the unit region to be processed next to obtain position information for moving the substrate to be processed;
(E) moving the substrate to be processed based on the positional information obtained in the step d;
(F) The processing apparatus according to claim 10, wherein the holding table is controlled such that a step of performing processing on the unit regions arranged at processing positions in the step e is sequentially executed. Furthermore, it has a beam source for irradiating an energy beam to a unit region arranged at the processing position,
The said control apparatus is a processing apparatus of Claim 11 which controls the said beam source so that an energy beam is irradiated to the unit area | region arrange | positioned in the said process position in the said process b and the process f.

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