JP7378250B2 - Imprint device and article manufacturing method - Google Patents

Description

The present invention relates to an imprint apparatus and a method for manufacturing an article.

2. Description of the Related Art An imprint apparatus that forms a pattern of an imprint material on a substrate using a mold (original plate) on which an uneven pattern is formed is attracting attention as one of the lithography apparatuses for mass production of semiconductor devices and the like. In an imprint apparatus, a die-by-die alignment method may be adopted as a method for positioning processing (alignment processing) between a mold and a substrate. The die-by-die alignment method optically detects the marks provided on the original and the marks provided on the substrate for each of multiple shot areas on the substrate, and corrects the misalignment in the positional relationship between the original and the substrate. This is an alignment method.

In an imprint apparatus that employs a die-by-die alignment method, the overlay accuracy between a pattern already formed on a substrate and a pattern formed on an imprint material on the substrate may differ from shot area to shot area. Therefore, in an imprint apparatus, it is desirable to inspect the overlay accuracy within the apparatus so that the overlay accuracy inspection result can be promptly reflected in subsequent alignment processing. Patent Documents 1 and 2 disclose imprint apparatuses configured to be able to inspect overlay accuracy within the apparatus.

Japanese Patent Application Publication No. 2011-97025 JP2009-88264A

The alignment process is performed based on images obtained by capturing the marks on the mold and the mark on the board, whereas the overlay inspection is performed based on the images obtained by capturing the marks on the board and the marks formed (transferred) on the imprint material. This can be done based on an image obtained by capturing the image. However, in an image obtained by overlay inspection, the signal intensity of the mark formed on the imprint material is much smaller than the signal intensity of the mark on the substrate. Therefore, if the overlay inspection is performed under the same conditions as the alignment process, the mark may not be detected from the image obtained by the imaging unit, or the mark may be detected incorrectly.

Therefore, an object of the present invention is to provide an advantageous technique for performing alignment processing and overlay inspection with high accuracy.

In order to achieve the above object, an imprint apparatus according to one aspect of the present invention is an imprint apparatus that forms a pattern on an imprint material on a substrate using an original, and includes an imaging unit that images the substrate. , an alignment process between the original plate and the substrate during pattern formation, and a pattern formed on the imprint material based on a fine inspection mark and a rough inspection mark in the image obtained by the imaging unit; a processing unit that performs an overlay inspection with the substrate, and the processing unit is configured to select a rough inspection mark group to be used for specifying the position of the fine inspection mark in the image obtained by the imaging unit at the position. The rough inspection mark group is selected from one or more rough inspection marks provided on the original plate and a plurality of rough inspection marks provided on the substrate. and a first rough inspection mark group as the rough inspection mark group used in the alignment process includes the one or more rough inspection marks on the original plate and at least one of the plurality of rough inspection marks on the substrate. The second rough inspection mark group as the rough inspection mark group used in the overlay inspection is characterized by comprising at least two of the plurality of rough inspection marks on the substrate.

Further objects or other aspects of the invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

According to the present invention, it is possible to provide an advantageous technique for performing alignment processing and overlay inspection with high precision, for example.

FIG. 1 is a schematic diagram showing the configuration of an imprint apparatus. FIG. 2 is a schematic diagram showing an example of the configuration of an imaging section. FIG. 3 is a diagram showing the relationship between the distribution of illumination light on the pupil plane of the illumination optical system and the numerical aperture of the imaging optical system. FIG. 3 is a diagram showing a grating pattern of a diffraction grating (examination mark) constituting a mark and moiré fringes caused by overlapping diffracted lights. It is a figure which shows the grating pattern of a diffraction grating. FIG. 3 is a diagram for explaining imprint processing. FIG. 3 is a diagram showing an example of a conventional configuration of marks on a mold M and marks on a substrate W. 5 is a diagram showing an example of the configuration of marks on a mold M and marks on a substrate W in Example 1. FIG. 3 is a diagram showing an image obtained by an imaging unit in Example 1. FIG. 5 is a flowchart showing alignment processing and overlay inspection. 7 is a diagram showing an example of the configuration of marks on a mold M and marks on a substrate W in Example 2. FIG. 7 is a diagram showing an image obtained by an imaging unit in Example 2. FIG. 7 is a diagram illustrating an example of the configuration of marks on a mold M and marks on a substrate W in a second embodiment. FIG. It is a figure which shows the image obtained by the imaging part in 2nd Embodiment. It is a figure which shows the image obtained by the imaging part in 3rd Embodiment. It is a figure showing a manufacturing method of an article.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same reference number is attached|subjected about the same member thru|or element, and the overlapping description is abbreviate|omitted.

<First embodiment>
An imprint apparatus 100 according to a first embodiment of the present invention will be described. Here, an imprint apparatus using a photocuring method will be described. FIGS. 1A and 1B are schematic diagrams showing the configuration of an imprint apparatus 100 of this embodiment. The imprint apparatus 100 performs an imprint process in which a pattern is formed on an imprint material on a substrate using a mold M (original plate). The imprint apparatus 100 includes, for example, an imprint head 1 that holds a mold M on which a predetermined uneven pattern is formed, a substrate stage 2 that is movable while holding a substrate W, an imaging section 6, and a control section 10. may include. Although not shown in FIG. 1, the imprint apparatus 100 may also include a supply unit (dispenser) that supplies (discharges) an imprint material onto the substrate.

The imprint apparatus 100 uses the imprint head 1 to narrow the distance between the mold M and the substrate W, and brings the mold M (pattern surface) into contact with the imprint material supplied onto the substrate. Then, with the mold M and the imprint material on the substrate in contact, the imprint material is irradiated with ultraviolet rays 7 to cure the imprint material, and the mold M is separated from the cured imprint material (separated). type). Thereby, a pattern of the imprint material can be formed on the substrate.

The imprint apparatus 100 is also provided with an imaging unit 6 (scope) that images (observes) the marks 4 provided on the mold M and the marks 5 provided on the substrate W. The imaging unit 6 can be placed inside the imprint head 1 as shown in FIG. 1(a), but if it is difficult to arrange the imaging unit 6 inside the imprint head 1, 1(b), it may be placed outside the imprint head 1. In the example shown in FIG. 1B, the imaging unit 6 can image the mark 4 on the mold M and the mark 5 on the substrate W via the imaging optical system 8. Further, the imaging unit 6 can image moire fringes generated by the light from the mark 4 of the mold M and the light from the mark 5 of the substrate W. The imaging optical system 8 shown in FIG. 1(b) may include an optical member such as a prism 8a having a property of reflecting ultraviolet rays 7 for curing the imprint material and transmitting light from the imaging section 6.

Here, the marks 4 and 5 captured by the imaging unit 6 may each include a fine inspection mark and a rough inspection mark as mark elements. The inspection mark is a mark for detecting the relative position between the mold M and the substrate W with high precision, and may include, for example, a diffraction grating. The rough inspection mark is a mark for detecting the relative position of the mold M and the substrate W with lower accuracy than the fine inspection mark, that is, for specifying the position of the fine inspection mark. To explain the fine inspection mark and the rough inspection mark conceptually, for example, when the relative position between the mold M and the substrate W is expressed as a two-digit value, the relative position in the tens place is measured by the rough inspection mark. , the relative position in the ones place can be measured by a fine inspection mark. Details of the fine inspection mark and rough inspection mark will be described later.

The control unit 10 includes, for example, a CPU and a memory, and controls the entire imprint apparatus 100 (each part of the imprint apparatus 100). For example, the control unit 10 moves the imprint head 1 and the substrate stage 2 in the XY directions based on the image obtained by the imaging unit 6, and performs a positioning process (alignment process) between the mold M and the substrate W. can be controlled. Further, the control unit 10 can control an overlay inspection between the pattern formed on the imprint material and the pattern already formed on the substrate W based on the image obtained by the imaging unit 6. As described above, the control section 10 of this embodiment has a function as a processing section that performs alignment processing and overlay inspection, but it may be configured separately from the processing section.

Configuration of Imaging Unit Next, the configuration of the imaging unit 6 will be explained in detail. FIG. 2 is a schematic diagram showing an example of the configuration of the imaging section 6. As shown in FIG. The imaging unit 6 may include an imaging optical system 21, an illumination optical system 22, and an imaging element 25 (for example, a CCD sensor or a CMOS sensor). The optical path of the imaging optical system 21 and the optical path of the illumination optical system 22 partially overlap, and an optical member such as a prism 24 is arranged in the overlapped part. In this configuration, a part of the optical axis of the imaging optical system 21 and a part of the optical axis of the illumination optical system 22 are common.

The illumination optical system 22 guides light from a light source 23 onto the same optical axis as the imaging optical system 21 through a prism 24, and illuminates the mark 4 on the mold M and the mark 5 on the substrate W. The light source 23 may be one that emits light of a wavelength different from the wavelength of the ultraviolet light 7, and may include, for example, a halogen lamp or an LED. In this embodiment, since ultraviolet light 7 is used as light for curing the imprint material, the light source 23 may be one that emits visible light or ultraviolet light.

The imaging optical system 21 images the marks 4 and 5 illuminated by the illumination optical system 22 on the light receiving surface of the imaging element 25. For example, the imaging optical system 21 detects a pattern (moiré fringes) generated by light diffracted by the inspection mark (diffraction grating) of mark 4 and the inspection mark (diffraction grating) of mark 5, which is detected by the image sensor 25. Image is formed on a surface. Thereby, the image sensor 25 can capture a moire image generated by the mark 4 of the mold M and the mark 5 of the substrate W. The image data obtained by the imaging unit 6 (image sensor 25) in this way is transmitted to the control unit 10, and the control unit 10 analyzes the phase of the moire generated based on the position of the mark in the image. The relative position between the mold M and the substrate W can be determined.

The prism 24 shared by the imaging optical system 21 and the illumination optical system 22 is preferably arranged at or near the pupil plane of the imaging optical system 21 and the illumination optical system 22. The prism 24 has a reflective film 24a on its bonded surface for reflecting light from a peripheral portion of the pupil plane of the illumination optical system 22. The reflective film 24a functions as an aperture stop that defines the distribution (shape) of illumination light on the pupil plane of the illumination optical system 22. Further, the reflective film 24a can also function as an aperture stop that defines the pupil size of the imaging optical system 21 (or the numerical aperture NA ₀ of the imaging optical system 21).

The prism 24 may be a half prism having a semi-transparent film on its bonded surface, or may be replaced by a plate-shaped optical element having a reflective film on its surface. Further, a plurality of prisms 24 having different aperture shapes may be provided so that the distribution of illumination light of the illumination optical system 22 and the size of the pupil of the imaging optical system 21 can be changed. In this case, the plurality of prisms 24 may be configured such that the prisms arranged on the optical path can be replaced by a switching mechanism such as a turret or a slide mechanism. In this embodiment, the distribution of illumination light on the pupil plane of the illumination optical system 22 is defined by the reflective film 24a of the prism 24, but for example, a mechanical diaphragm or a drawing on the glass surface may be used at the pupil position of the illumination optical system 22. It can also be defined by arranging a diaphragm or the like.

FIG. 3 is a diagram showing the relationship between the distribution of illumination light (IL1 to IL4) on the pupil plane of the illumination optical system 22 and the numerical aperture NA ₀ of the imaging optical system 21. In this embodiment, the distribution of illumination light on the pupil plane of the illumination optical system 22 consists of four poles IL1 to IL4. As described above, by arranging the reflective film 24a that functions as an aperture stop on the pupil plane of the illumination optical system 22, it is possible to form a light intensity distribution having a plurality of poles (IL1 to IL4) from one light source 23. can. When forming a light intensity distribution having a plurality of poles (peaks) in this way, a plurality of light sources are not required, so the imaging section 6 can be simplified or downsized.

FIGS. 4A to 4D are diagrams showing a grating pattern of a diffraction grating (precise inspection mark) constituting a mark and moiré fringes caused by overlapping diffracted lights. FIGS. 4A and 4B are diagrams respectively showing diffraction gratings 31 and 32 whose grating pattern periods are slightly different from each other. When these diffraction gratings 31 to 32 are superimposed, a pattern (moiré fringes) having a period reflecting the difference in period is generated by the diffracted light from each diffraction grating, as shown in FIG. 4(c). The phase (position of brightness and darkness) of the moiré fringes changes depending on the relative positions of the diffraction gratings. For example, if the diffraction gratings 31 and 32 are relatively shifted slightly in the X direction, the moire fringes shown in FIG. 4(c) change as shown in FIG. 4(d). The phase of these moiré fringes changes with a larger period than the magnitude of the actual relative position change of the two diffraction gratings, so even if the resolution of the imaging unit 6 is low, the relative positions of the two diffraction gratings can be accurately measured. can do. That is, the marks 4 on the mold M and the marks 5 on the substrate W are each formed of diffraction gratings with slightly different periods, and the relative position between the mold M and the substrate W can be measured by observing the moire fringes. .

FIGS. 5(a) to 5(d) are diagrams showing grating patterns of diffraction gratings forming the mark of this embodiment. When attempting to detect moire fringes using a bright field configuration (illumination from the vertical direction and detection of diffracted light from the vertical direction), the contrast of the moire fringes decreases due to the influence of zero-order light. Therefore, in this embodiment, one of the mark 4 of the mold M and the mark 5 of the substrate W is set as shown in FIG. The diffraction grating has a checkerboard shape as shown in (a) and (c).

When the combination of diffraction gratings shown in FIGS. 5(a) to 5(b) is illuminated with illumination light having a light intensity distribution having poles IL1 to IL4 as shown in FIG. The light is also diffracted in the Y direction. This diffracted light enters the imaging optical system 21 (NA ₀ ) with relative position information in the X direction and is detected by the imaging element 25. Therefore, based on the image obtained by the image sensor 25, the relative positions of the two diffraction gratings in the X direction can be measured. Here, in the combination of diffraction gratings shown in FIGS. 5(a) and 5(b), the illumination light from the poles IL1 and IL2 is used when measuring their relative positions, and the illumination light from the poles IL3 and IL4 is Not used.

Similarly, when the combinations of diffraction gratings shown in FIGS. 5(c) to (d) are illuminated with illumination light having a light intensity distribution having poles IL1 to IL4 as shown in FIG. 3, the diffraction gratings in FIG. 5(c) The light incident on is also diffracted in the X direction. This diffracted light enters the imaging optical system 21 (NA ₀ ) with relative position information in the Y direction and is detected by the imaging element 25. Therefore, based on the image obtained by the image sensor 25, the relative positions of the two diffraction gratings in the Y direction can be measured. Here, in the combination of diffraction gratings shown in FIGS. 5(c) to 5(d), the illumination light from the poles IL3 to IL4 is used when measuring their relative positions, and the illumination light from the poles IL1 to IL2 is Not used.

In this way, the imaging unit 6 of this embodiment images the diffraction grating shown in FIG. 5 using the illumination light having the light intensity distribution shown in FIG. direction, Y direction) can be measured. That is, the set of diffraction gratings shown in FIGS. 5(a) to 5(b) and the set of diffraction gratings shown in FIGS. 5(c) to 5(d) are arranged and imaged within the same field of view of the imaging unit 6. Thereby, relative positions in two directions (X direction, Y direction) can be measured simultaneously and with high precision.

Imprint Processing Next, the imprint processing by the imprint apparatus 100 will be described. FIG. 6 is a diagram for explaining the imprint process, and shows the mold M and the substrate W. In the imprint process, the substrate W to which the imprint material 3 in the form of droplets has been supplied is placed below the mold M, as shown in FIG. 6(a). Note that the imprint material 3 may be supplied onto the substrate for each shot area, or may be supplied in advance over the entire surface of the substrate at once. Then, as shown in FIG. 6(b), the distance between the mold M and the substrate W is narrowed, the mold M is brought into contact with the imprint material 3 on the substrate, and the uneven pattern of the mold M is filled with the imprint material. . In the steps shown in FIGS. 6(a) and 6(b) (at the time of pattern formation), the marks 4 of the mold M and the marks 5 of the substrate W are captured by the imaging unit 6, and based on the image obtained, the marks 4 of the mold M and the marks 5 of the substrate W are An alignment process with the substrate W is performed. After the alignment process is completed, the imprint material 3 on the substrate is irradiated with light (ultraviolet light 7) through the mold M to harden the imprint material 3, as shown in FIG. 6(c). The mold M is peeled off (released) from the imprint material 3. The mark 4 of the mold M is transferred to the imprint material 3 on the substrate on which the pattern has been formed in this way, as shown as a transfer mark 3a in FIG. 6(c).

Mark configuration Mark elements used to measure the relative position between the mold M and the substrate W generally have a contradictory relationship between measurement accuracy (resolution of relative position) and measurement range (measurable range of relative position). It is in. For example, as described above, the mark element (precise inspection mark) composed of a diffraction grating can measure the relative position between the mold M and the substrate W within one period of the moire fringes with high precision. High accuracy. On the other hand, the measurement range is narrow because it is not possible to measure the shift of the moiré fringes for each cycle (by cycle). Therefore, in addition to a fine inspection mark with high measurement accuracy but a narrow measurement range, a rough inspection mark with low measurement accuracy but a wide measurement range is provided as mark elements for the mark 4 of the mold M and the mark 5 of the substrate W, respectively. It will be done. By detecting these mark elements (fine inspection marks, rough inspection marks) within the same field of view of the imaging unit 6, it is possible to achieve both high measurement accuracy and a wide measurement range. That is, the position of the fine inspection mark can be specified using the detection result of the rough inspection mark, and the relative position between the mold M and the substrate W can be adjusted so that the fine inspection mark falls within a desired measurement range.

FIG. 7 is a diagram showing a conventional configuration example of the mark 4 on the mold M and the mark 5 on the substrate W. FIG. 7(a) shows an example of the conventional configuration of the mark 4 of the mold M. The mark 4 includes an inspection mark 41 composed of a diffraction grating, and a measurement range by specifying the position of the inspection mark. It may have a rough inspection mark 42 for fitting within the range. Further, FIG. 7(b) shows an example of the conventional configuration of the mark 5 on the substrate W, and the mark 5 includes an inspection mark 51 composed of a checkerboard-shaped diffraction grating and a position of the inspection mark. It has a rough inspection mark 52 for specifying. By overlapping the inspection mark 41 of the mark 4 of the mold M and the inspection mark 51 of the mark 5 of the substrate W, moiré fringes can be generated.

FIG. 7(c) shows an image obtained by imaging a state in which mark 4 shown in FIG. 7(a) and mark 5 shown in FIG. 7(b) overlap in the positioning process during imprint processing using the imaging unit 6. The image 60 shown in FIG. The control unit 10 performs rough alignment based on the relative positions of the rough inspection marks 42 and 52 in the image (in the image 60) (that is, keeps the positions of the fine inspection marks 41 and 45 within the measurement range), and The positions (periods) of the inspection marks 41 and 51 are specified. Thereby, the relative position between the mold M and the substrate W can be determined based on the moire fringes 61 generated by the inspection marks 41 and 51.

Here, the mold M is made of a material such as quartz that transmits ultraviolet rays 7, and has a small difference in refractive index with respect to the imprint material supplied onto the substrate. Therefore, when the mold M and the imprint material come into contact and the mark 4 of the mold M formed as a recess is filled with the imprint material, it becomes difficult for the imaging unit 6 to detect the mark 4 of the mold M. . Therefore, the marks 4 (fine inspection mark 41, rough inspection mark 42) of the mold M have a metal film formed by vapor deposition or the like, and even if the mold M and the imprint material are in contact with each other, the imaging unit 4 It is configured so that it can be detected.

Further, in the image 60 obtained by the imaging unit 6, it is preferable that the signal intensities of the mark 4 of the mold M and the mark 5 of the substrate W are close to each other in order to perform stable mark measurement. Therefore, in the mark 4 of the mold M, the size (dimensions) of the mark and the thickness of the metal film are adjusted so that the signal intensity in the image obtained by the imaging unit 6 approaches the signal intensity of the mark 5 of the substrate W. sell.

Since the overlay inspection imprint apparatus 100 employs a die-by-die alignment method, the overlay accuracy between the pattern already formed on the substrate W and the pattern formed on the imprint material on the substrate is as high as shot. May vary by area. Therefore, in the imprint apparatus 100, it is desirable to inspect the overlay accuracy within the apparatus so that the overlay accuracy inspection result can be promptly reflected in subsequent imprint processing. Further, at this time, it is preferable to image the substrate W under the same imaging conditions such as the magnification of the imaging section 6 in the alignment process and the overlay inspection.

For example, in the overlay inspection, as shown in FIG. 7(d), an image 70 obtained by capturing a mark on the substrate W and a mark formed (transferred) on the imprint material on the substrate by the imaging unit 6 is used. It is carried out based on. In the image 70 shown in FIG. 7(d), the rough inspection mark 42' indicates a mark formed on the imprint material on the substrate by transferring the rough inspection mark 42 of the mold M to the imprint material on the substrate. . Further, the moire stripes 61' are moire stripes formed by transferring the inspection mark 41 of the mold M to the imprint material on the inspection mark 51 of the substrate W.

In the image 70 obtained by the imaging unit 6 in the overlay inspection, the signal intensity of the rough inspection mark 42' formed on the imprint material is much smaller than the signal intensity of the rough inspection mark 52 on the substrate W. Particularly, as mentioned above, when the size of the mark is adjusted to match the signal strength during imprint processing, the material of the rough inspection mark changes, resulting in a noticeable difference. Therefore, in overlay inspection, if the group of rough inspection marks to be used to specify the position of the fine inspection mark is selected under the same conditions as the alignment process, the group of rough inspection marks cannot be found. Otherwise, the rough inspection mark may be mistakenly detected.

Therefore, the control unit 10 of the present embodiment changes the rough inspection mark group to be used to specify the position of the detailed inspection mark in the image obtained by the imaging unit 6 in the alignment process and the overlay inspection ( ). Specifically, in the alignment process, a group of rough inspection marks arranged in a first positional relationship is selected in the image obtained by the imaging unit 6, and based on the position of the selected group of rough inspection marks, Locate the inspection mark. On the other hand, in overlay inspection, a group of rough inspection marks arranged in a second positional relationship different from the first positional relationship is selected, and the position of the fine inspection mark is determined based on the position of the selected group of rough inspection marks. Identify. The details of this embodiment will be explained below.

[Example 1]
Example 1 of this embodiment will be described. FIG. 8 is a diagram showing a configuration example of the mark 4 on the mold M and the mark 5 on the substrate W in Example 1 of the present embodiment. FIG. 8A shows an example of the structure of the mark 4 on the mold M, and FIG. 8B shows an example of the structure of the mark 5 on the substrate W. Further, FIG. 9 is a diagram showing an image obtained by the imaging section 6. FIG. 9(a) shows an image 60 obtained by the imaging section 6 in the alignment process, and FIG. 9(b) shows an image 70 obtained by the imaging section 6 in the overlay inspection. Here, "the image obtained by the imaging unit 6" refers to the field of view of the imaging unit 6, that is, the 25 imageable areas (observable areas) of the image sensor.

First, the alignment process according to the first embodiment will be described with reference to FIG. 10(a). FIG. 10(a) is a flowchart showing the alignment process. In S11, as shown in FIG. 9A, the control unit 10 sets the search range of the rough inspection mark group used for specifying the position of the fine inspection mark in the image 60 obtained by the imaging unit 6 to the first Set range R to ₁ . The search range is a range (also referred to as a measurement range) in which a search process for a group of rough inspection marks is performed in an image. In S12, the control unit 10 selects (searches for) a group of rough inspection marks arranged in the first positional relationship from within the search range set as the first range _R1 . The information on the first positional relationship is set in advance by the user via the user interface provided in the imprint apparatus 100, and in this embodiment, the information on the first positional relationship is the first positional relationship between the two rough inspection marks arranged in the Y direction. It is set as a 1-position relationship. In the example shown in FIG. 9A, the rough inspection mark 42 of the mold M and the rough inspection mark 52a of the substrate W are selected as a group of rough inspection marks arranged in a first positional relationship. In S13, the control unit 10 aligns the mold M and the substrate W based on the selected group of rough inspection marks. In S14, the control unit 10 specifies the position of the fine inspection mark based on the selected rough inspection mark group. In S15, the control unit 10 aligns the mold M and the substrate W based on the moire fringes 61 in the inspection mark.

Next, the overlay inspection according to Example 1 will be explained with reference to FIG. 10(b). FIG. 10(b) is a flowchart showing the overlay inspection. In S21, as shown in FIG. 9(b), the control unit 10 changes the search range of the rough inspection mark group used for specifying the position of the fine inspection mark in the image 70 obtained by the imaging unit 6 to the second Set to range _R2 . The second range _R2 is set to be wider than the first range _R1 so that the number of rough inspection marks included in the search range is greater than that in the alignment process.

In S22, the control unit 10 selects (searches for) a group of rough inspection marks arranged in the second positional relationship from within the search range set as the second range _R2 . The image 70 used in the overlay inspection includes a rough inspection mark 42' formed on the imprint material, and the signal intensity of the rough inspection mark 42' in the image 70 is very small. Therefore, it is not preferable to select the rough inspection marks 42' formed on the imprint material as part of a group of rough inspection marks for specifying the positions of the detailed inspection marks. Therefore, in the first embodiment, the positional relationship between the rough inspection marks 52a to 52c on the substrate W is determined in advance by the user via the user interface as the second positional relationship so that the mark 42' formed on the imprint material is not selected. Set. Thereby, the control unit 10 can select the rough inspection marks 52a to 52c arranged in the second positional relationship in the image 70 as a group of rough inspection marks for specifying fine inspection marks. In S23, the control unit 10 specifies the position of the fine inspection mark based on the selected rough inspection mark group. In S24, the control unit 10 determines (calculates) the overlay error between the mold M and the substrate W based on the moire fringes 61' in the inspection mark.

Here, the second positional relationship is such that the rough inspection mark group selected in the alignment process and the rough inspection mark group selected in the overlay inspection commonly include at least one rough inspection mark of the substrate W. It is recommended that it be set to . Thereby, the information used when specifying the position of the fine inspection mark from the position of the rough inspection mark group during the alignment process can be referenced (used) during the overlay inspection. In other words, the accuracy of identifying the position of the inspection mark can be brought closer (matched) by the alignment process and the overlay inspection. In the example shown in FIG. 9B, the rough inspection mark 52a of the substrate W can be commonly selected in the alignment process and the overlay inspection.

Further, when measuring in the first range R1, a pattern having a positional relationship between the marks 42 and 52a is searched as a rough inspection mark. For this reason, it is preferable that the positional relationship between the marks 52b and 52c used in the second range R2 is not the positional relationship between the marks 42 and 52 described above. The number of marks used in the second range R2 may be changed.

As described above, in the alignment process, the position of the fine inspection mark is specified in the image 60 obtained by the imaging unit 6 based on the group of rough inspection marks arranged in the first positional relationship. On the other hand, in the superposition process, the position of the fine inspection mark is specified in the image 70 obtained by the imaging unit 6 based on a group of rough inspection marks arranged in a second positional relationship different from the first positional relationship. Thereby, the imaging section 6 can perform imaging under the same imaging conditions during the alignment process and the overlay inspection. In addition, during overlay inspection, the rough inspection mark formed on the imprint material is prevented from being selected as part of the group of rough inspection marks used to specify the position of the fine inspection mark, and the overlay is performed with high precision. Tests can be carried out.

[Example 2]
Example 2 of this embodiment will be described. In the second embodiment, the rough inspection mark group used to specify the position of the fine inspection mark in the overlay inspection includes a part of the pattern already formed on the substrate W. Thereby, the position of the fine inspection mark can be specified with high accuracy without newly providing the rough inspection mark, which is used only for overlay inspection, on the substrate W.

FIG. 11 is a diagram showing a configuration example of the mark 4 on the mold M and the mark 5 on the substrate W in Example 2 of the present embodiment. FIG. 11A shows an example of the structure of the mark 4 on the mold M, and FIG. 11B shows an example of the structure of the mark 5 on the substrate W. In addition to the mark 5, a part 53 of the pattern already formed on the substrate W is shown in FIG. 11(b). Further, FIG. 12 is a diagram showing an image obtained by the imaging section 6. FIG. 12(a) shows an image 60 obtained by the imaging section 6 in the alignment process, and FIG. 12(b) shows an image 70 obtained by the imaging section 6 in the overlay inspection.

Similar to the first embodiment, the positioning process according to the second embodiment is performed according to the flowchart shown in FIG. 10(a). Specifically, as shown in FIG. 12(a), the control unit 10 selects a group of rough inspection marks (of the mold M) arranged in a first positional relationship from within the search range set as the first range _R1 . Rough inspection mark 42 and rough inspection mark 52) of substrate W are selected. Then, the position of the fine inspection mark is specified based on the position of the selected group of rough inspection marks, and the mold M and the substrate W are aligned based on the moire fringes 61 formed by the fine inspection mark.

The overlay inspection according to the second embodiment is also performed in accordance with the flowchart shown in FIG. 10(b), similarly to the first embodiment. Specifically, the control unit 10 selects a group of rough inspection marks arranged in the second positional relationship from within the search range set as the second range _R2 , as shown in FIG. 12(b). However, in the second embodiment, the second positional relationship is set such that the part 53 of the pattern already formed on the substrate W is used as a part of the rough inspection mark group for specifying the position of the fine inspection mark. sell. Then, the position of the fine inspection mark is specified based on the position of the selected rough inspection mark group (rough inspection mark 42 of the mold M, part of the pattern 53 of the substrate W), and the moire fringes 61' in the fine inspection mark are Based on this, the overlay error between the mold M and the substrate W is determined.

In this way, even if a part of the pattern already formed on the substrate is used as part of the rough inspection mark group used to specify the position of the fine inspection mark in the overlay inspection, the same effect as in Example 1 can be obtained. can be obtained.

<Second embodiment>
An imprint apparatus according to a second embodiment of the present invention will be described. The imprint apparatus of the second embodiment has the same configuration as the imprint apparatus 100 of the first embodiment. The imprint apparatus of the second embodiment performs alignment processing based on a first image obtained by capturing images of the first mark provided on the substrate and the mark of the mold M with the imaging unit 6. Further, an overlay inspection is performed based on a second image obtained by imaging a second mark provided at a different position on the substrate from the first mark by the imaging unit 6 without using the mold M.

13(a) is a diagram showing a first mark 4a and a second mark 4b provided at mutually different positions on the mold M, and FIG. 13(b) is a diagram showing a first mark 4a and a second mark 4b provided at mutually different positions on the substrate W. 5 is a diagram showing a first mark 5a and a second mark 5b. FIG. Further, FIG. 14(a) shows that during alignment, the marks on the mold M (FIG. 13(a)) and the marks on the substrate W (FIG. 13(b)) are superimposed and imaged by the imaging unit 6. 6 is a diagram showing an obtained image 60. FIG. The image 60a on the left side in FIG. 14A is an image obtained by superimposing images of the first mark 4a of the mold M and the first mark 5a of the substrate W. Further, the image 60b on the right side is an image obtained by superimposing images of the second mark 4b of the mold M and the second mark 5b of the substrate W. FIG. 14(b) shows that in the overlay inspection, the mark on the substrate W (FIG. 13(a)) and the mark formed (transferred) on the imprint material on the substrate are detected by the imaging unit 6 without using the mold M. It is a figure which shows the image obtained by imaging with. The image 70a on the left side of FIG. 14(b) is an image obtained by capturing the first mark 5a on the substrate W, and the image 70b on the right side is an image obtained by capturing the second mark 5b on the substrate W. be.

The positioning process is performed based on an image 60a (first image) obtained by superimposing the first mark 4a of the mold M and the first mark 5a of the substrate W and capturing the images with the imaging unit 6. The first mark 4a of the mold M is configured to include a fine inspection mark 41 (diffraction grating) and a rough inspection mark 42, as shown in FIG. 13(a). Further, the first mark 5a of the substrate W is configured to include a fine inspection mark 51 (diffraction grating) and a rough inspection mark 52, as shown in FIG. 13(b). Therefore, when the first mark 4a of the mold M and the first mark 5a of the substrate W are imaged by the imaging unit 6 in an overlapping manner, an image 60a (first image) on the left side of FIG. 14(a) is obtained. The control unit 10 specifies the position (period) of the fine inspection mark based on the position of the rough inspection mark group (42, 52) in the first image 60a, and specifies the position (period) of the fine inspection mark based on the moire fringe 61 generated by the fine inspection mark. Thus, the relative position between the mold M and the substrate W can be determined.

On the other hand, in the overlay inspection, as shown in the image 70a on the left side of FIG. It becomes very small compared to the signal strength. Therefore, the overlay inspection of this embodiment is performed based on the image on the right side of FIG. 14(b) (the image 70b (second image) obtained by imaging the second mark 5b of the substrate W). The second mark 5b on the substrate W is configured such that the mark configuration of the second image 70b is the same as the mark configuration of the first image 60a. Specifically, the second mark 4b of the mold M is configured to include only the fine inspection mark 41 without including the rough inspection mark, as shown in FIG. 13(a). Further, the second mark 5b of the substrate W is configured to include a plurality of rough inspection marks 52 so as to compensate for the rough inspection mark in the second mark 4b of the mold M.

With this configuration, it is possible to obtain similar signal intensities with the same mark configuration in the first image 60a used in alignment processing and the second image 70b used in overlay inspection. Therefore, the alignment process and the superimposition process can be performed without changing the imaging conditions of the imaging unit 6 and the rough inspection mark search conditions.

<Third embodiment>
An imprint apparatus according to a third embodiment of the present invention will be described. The imprint apparatus of the third embodiment has the same configuration as the imprint apparatus 100 of the first embodiment. The imprint apparatus of the third embodiment performs alignment processing based on a first image obtained by capturing images of the first mark provided on the substrate and the mark of the mold M by the imaging unit 6.

At this time, the size of the first mark may vary due to manufacturing errors on the substrate side, or the signal intensity from the first mark may vary depending on the relationship between the multilayer films formed on the substrate. In particular, since the rough inspection mark has a different structure and material between the mark provided on the substrate and the mark of the mold M, the signal strength difference may change. If the change is within the allowable range, it can be measured as is. However, if a change in signal intensity occurs that exceeds the measurable range, it may become impossible to measure the rough inspection mark, and alignment measurement may no longer be possible.

Such problems can be addressed by the mark configuration described in the above embodiment. For example, the case of the mark configuration explained in FIG. 9 will be explained. As shown in FIG. 9A, mark detection during normal imprinting involves alignment measurement using the fine inspection mark 61, the rough inspection mark 42 of the mold M, and the rough inspection mark 52a of the substrate W. As described above, in alignment measurement, it is necessary to quickly perform search processing from the obtained image 60, so the first range _R1 , which is the detection range, is made as small as possible. At this time, if the rough inspection mark 52a has a defect and cannot be detected, alignment measurement cannot be performed.

Therefore, if a problem occurs with the rough inspection mark 52a, the rough inspection marks 52b and 52c of the substrate W are used during alignment measurement. If the rough inspection mark 52a cannot be used, the detection range is set to the second range _R2 as shown in FIG. 9(b). In this way, the detection range is expanded to include the rough inspection marks 52b and 52c. By determining the relative position between the rough inspection mark 52b (52c) and the rough inspection mark 42, the mold M and the substrate W are aligned. Thereby, even if there is a defect in the rough inspection mark 52a, alignment measurement can be performed.

In addition, if the signal strength of the rough inspection mark 52a is significantly different from that of the rough inspection mark 42 and the fine inspection mark 61, even if the light is adjusted, the fine inspection mark 61, the rough inspection mark 42 of the mold M, and the rough inspection mark 52a of the board W In some cases, it may not be possible to obtain an appropriate signal strength between the two.

Therefore, as shown in FIG. 15, for example, the rough inspection mark 52d of the substrate W can be made smaller than the rough inspection mark 52a, or the rough inspection mark 52e of the substrate W can be made larger than the rough inspection mark 52a. FIG. 15 shows the state when marks are detected during imprinting. As shown in FIG. 15, by forming rough inspection marks for the substrate W of various sizes, if the rough inspection mark 52a is not suitable for alignment measurement, an appropriate rough inspection mark (52d or 52e) can be selected. You can adjust the signal strength with . As shown in FIG. 15, the intensity of light (signal intensity) from the rough inspection mark on the substrate W can be adjusted by changing the shape of the second mark provided at a position on the substrate different from that of the first mark. I can do it.

The mark to be added (second mark) is not limited to the rough inspection mark of the substrate W, but may be the rough inspection mark of the mold M. In that case, a rough inspection mark of the mold M having a signal intensity close to that of the rough inspection mark 52a of the substrate W is selected. Furthermore, several rough inspection marks may be configured for each of the substrate W and the mold M, and a combination that provides the most appropriate signal strength may be selected. The signal strength may be adjusted not only by the size of the mark but also by the degree and shape of the segment.

Furthermore, as shown in the second embodiment, similar measurements can be performed even for a part of the pattern formed on the substrate by acquiring the pattern in advance and measuring the signal intensity ratio. .

With such a configuration, even if there is a problem with the rough inspection mark 52a of the substrate W during alignment processing, alignment measurement can be continued without stopping due to an error. For example, this can help avoid errors when performing alignment measurements on a large number of substrates, such as when manufacturing actual devices.

<Embodiment of article manufacturing method>
The article manufacturing method according to the embodiment of the present invention is suitable for manufacturing articles such as micro devices such as semiconductor devices and elements having fine structures. The method for manufacturing an article of the present embodiment includes a step of forming a pattern on an imprint material supplied (applied) to a substrate using the above imprint device (imprint method), and a step of forming a pattern on an imprint material supplied (applied) to a substrate, and and processing the substrate. Additionally, such manufacturing methods include other well-known steps (oxidation, deposition, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The method for manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to conventional methods.

A pattern of a cured product formed using an imprint device is used permanently on at least a portion of various articles, or temporarily when manufacturing various articles. The articles include electric circuit elements, optical elements, MEMS, recording elements, sensors, molds, and the like. Examples of the electric circuit element include volatile or nonvolatile semiconductor memories such as DRAM, SRAM, flash memory, and MRAM, and semiconductor elements such as LSI, CCD, image sensor, and FPGA. Examples of the mold include a mold for imprinting and the like.

The pattern of the cured product can be used as it is as a component of at least a portion of the article, or can be used temporarily as a resist mask. After etching, ion implantation, or the like is performed in a substrate processing step, the resist mask is removed.

Next, a specific method for manufacturing the article will be described. As shown in FIG. 16(a), a substrate 1z such as a silicon wafer on which a workpiece 2z such as an insulator is formed is prepared, and then ink is applied to the surface of the workpiece 2z by an inkjet method or the like. Apply printing material 3z. Here, a state in which a plurality of droplet-shaped imprint materials 3z are applied onto a substrate is shown.

As shown in FIG. 16(b), the imprint mold 4z is placed so that the side on which the concavo-convex pattern is formed faces the imprint material 3z on the substrate. As shown in FIG. 16(c), the substrate 1z to which the imprint material 3z has been applied is brought into contact with the mold 4z, and pressure is applied. The imprint material 3z is filled into the gap between the mold 4z and the workpiece 2z. In this state, when light is irradiated as energy for curing through the mold 4z, the imprint material 3z is cured.

As shown in FIG. 16(d), after the imprint material 3z is cured, when the mold 4z and the substrate 1z are separated, a pattern of the cured imprint material 3z is formed on the substrate 1z. The pattern of this cured product has a shape in which the concave parts of the mold correspond to the convex parts of the cured product, and the convex parts of the mold correspond to the concave parts of the cured product.In other words, the concave and convex pattern of the mold 4z is transferred to the imprint material 3z. It means that it was done.

As shown in FIG. 16(e), when etching is performed using the pattern of the cured material as an etching-resistant mask, the portions of the surface of the workpiece 2z where there is no or a thin remaining cured material are removed, forming grooves 5z and Become. As shown in FIG. 16(f), when the pattern of the cured product is removed, an article in which grooves 5z are formed on the surface of the workpiece 2z can be obtained. Although the pattern of the cured product is removed here, it may be used as an interlayer insulation film included in a semiconductor element or the like, that is, as a component of an article, without removing it even after processing.

Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

1: Imprint head, 2: Substrate stage, 4: Mold M mark, 5: Substrate W mark, 6: Imaging section (scope), 10: Control section

Claims (13)

An imprint device that forms a pattern on an imprint material on a substrate using an original plate,
an imaging unit that images the substrate;
Based on the fine inspection mark and the rough inspection mark in the image obtained by the imaging unit, the alignment process of the original plate and the substrate during the pattern formation, and the alignment process of the pattern formed on the imprint material and the A processing unit that performs an overlay inspection with the substrate;
including;
The processing unit changes a group of rough inspection marks to be used for specifying the position of the detailed inspection mark in the image obtained by the imaging unit in the alignment process and the overlay inspection,
The rough inspection mark group is selected from one or more rough inspection marks provided on the original plate and a plurality of rough inspection marks provided on the substrate,
A first rough inspection mark group as the rough inspection mark group used in the alignment process includes the one or more rough inspection marks on the original plate and at least one of the plurality of rough inspection marks on the substrate,
An imprint apparatus characterized in that a second rough inspection mark group as the rough inspection mark group used in the overlay inspection is composed of at least two of the plurality of rough inspection marks on the substrate. An imprint device that forms a pattern on an imprint material on a substrate using an original plate,
an imaging unit that images the substrate;
Based on the fine inspection mark and the rough inspection mark in the image obtained by the imaging unit, the alignment process of the original plate and the substrate during the pattern formation, and the alignment process of the pattern formed on the imprint material and the A processing unit that performs an overlay inspection with the substrate;
including;
The processing unit includes:
A group of rough inspection marks to be used for specifying the position of the detailed inspection mark in the image obtained by the imaging unit is changed between the alignment process and the overlay inspection,
Among the images obtained by the imaging unit, a search range of a group of rough inspection marks used for specifying the position of the detailed inspection mark is set so that it is wider in the overlay inspection than in the alignment process. An imprint device featuring: The imprint apparatus according to claim 1 or 2, wherein the imaging unit images the substrate at the same magnification in the alignment process and the overlay inspection. The processing unit includes:
In the alignment process, in the image obtained by the imaging unit, the position of the fine inspection mark is specified based on the position of a group of rough inspection marks arranged in a first positional relationship,
In the overlay inspection, the position of the fine inspection mark is specified based on the position of a group of rough inspection marks arranged in a second positional relationship different from the first positional relationship in the image obtained by the imaging unit. ,
The imprint apparatus according to any one of claims 1 to 3, characterized in that: In the alignment process,
The imaging unit images the substrate via the original,
The insulator according to claim 4, wherein the group of rough inspection marks arranged in the first positional relationship consists of a rough inspection mark provided on the original plate and a rough inspection mark provided on the substrate. Printing device. In the overlay inspection,
The imaging unit images the substrate without using the original,
6. The imprint apparatus according to claim 4, wherein the group of rough inspection marks arranged in the second positional relationship consists of rough inspection marks provided on the substrate. The imprint according to any one of claims 4 to 6, wherein the group of rough inspection marks arranged in the second positional relationship includes a part of a pattern already formed on the substrate. Device. The rough inspection mark group used to specify the position of the fine inspection mark in the alignment process and the rough inspection mark group used to specify the position of the fine inspection mark in the overlay process are common marks provided on the substrate. 8. The imprint apparatus according to claim 1, further comprising at least one rough inspection mark. The processing unit includes :
performing the positioning process based on a first image obtained by imaging the first rough inspection mark group by the imaging unit;
performing the overlay inspection based on a second image obtained by imaging the second rough inspection mark group by the imaging unit without using the original;
The first rough inspection mark group and the second rough inspection mark group have a mark configuration that is different from the mark configuration of the first rough inspection mark group in the first image and the mark configuration of the second rough inspection mark group in the second image. The imprint apparatus according to claim 1 , wherein the imprint apparatuses are provided at different positions so as to be the same . The second rough inspection mark group does not include marks formed on the imprint material on the substrate by transferring the one or more rough inspection marks of the original plate through the pattern formation. The imprint apparatus according to claim 1. 2. The second rough inspection mark group includes at least one rough inspection mark that was not used in the alignment process among the plurality of rough inspection marks provided on the substrate. Imprint device as described. The processing unit includes:
In the alignment process, a group of rough inspection marks arranged in a first positional relationship in the image obtained by the imaging unit is selected as the first group of rough inspection marks,
In the overlay inspection, a group of rough inspection marks arranged in a second positional relationship different from the first positional relationship in the image obtained by the imaging unit is selected as the second group of rough inspection marks.
The imprint apparatus according to claim 1, characterized in that: forming a pattern on a substrate using the imprint apparatus according to any one of claims 1 to 12 ;
processing the substrate on which a pattern is formed,
A method for manufacturing an article, comprising manufacturing the article from the processed substrate.

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