JP6351412B2 - Imprint apparatus and method, article manufacturing method, and program - Google Patents

Description

  The present invention relates to an imprint apparatus and method for performing pattern formation on a substrate.

  The imprint apparatus includes a substrate stage, a resin coating mechanism, an imprint head, a light irradiation system, and an alignment mark detection mechanism for positioning. The imprint operation can be performed in a step-and-repeat manner as in a known exposure apparatus.

  In application of imprint technology to semiconductors, first, application to memory elements is considered. Memory devices have a problem of cost reduction by mass production, and the most effective method for cost reduction is miniaturization. Imprint technology has excellent microfabrication capability and is most suitable for memory device requirements. On the other hand, imprint processing defects are a significant risk of reducing the yield of semiconductor production. Examples of defects that occur in the mask include damage to the mask caused by particles adhering to the wafer, and clogging in which part of the cured resin remains in the mask when the mask is peeled off from the cured resin. These mask defects continuously cause transfer defects (repetitive defects) in subsequent shot areas to which imprint processing is performed. Patent Document 1 proposes a method of removing particles adhering to a mold using a dummy wafer. Specifically, a particle removal film with high adhesion to the photo-curable resin is applied on the dummy wafer, and then the photo-curable resin is applied on the dummy wafer and imprinted, whereby the particles adhering to the mold are photo-cured. It is taken into the functional resin and removed from the mold. Also, in Patent Document 2, when a foreign substance that may damage the mold is found on the wafer, the imprint process is performed by switching to a dummy mold that may perform the imprint process on the shot area including the foreign substance. A method is disclosed.

JP 2009-266841 A JP 2010-069762 A

  When imprint processing is performed with a dummy mold as disclosed in Patent Document 2, the entire shot area is imprinted with a dummy mold. For this reason, in the case where there is a pattern area for a plurality of chips in one shot area, even if a foreign substance exists only on one chip pattern, even a chip pattern without a foreign substance is imprinted with a dummy type. . Therefore, it can be said that the method of Patent Document 2 has room for improvement in terms of the yield of products (chips and the like).

  An object of the present invention is to provide an imprint technique that is advantageous in achieving both throughput and yield.

  One aspect of the present invention relates to an imprint apparatus that performs pattern formation on a plurality of regions on a substrate each corresponding to at least one product with a product pattern related to the product, and performs the pattern formation. An imprint unit; and a control unit that controls the operation of the imprint unit, wherein the control unit includes a part of the plurality of regions when a foreign object or a chip is present. The operation is controlled so that the pattern formation is performed with a mold having a different pattern different from the product pattern in a region corresponding to and having the product pattern in a region different from the partial region. It is characterized by that.

  According to the present invention, for example, it is possible to provide an imprint technique that is advantageous in achieving both throughput and yield.

The figure which shows the structure of the imprint apparatus in embodiment. The figure which shows the example of the pattern of 1 shot transcribe | transferred on a wafer. The enlarged view in 1 chip | tip of FIG. The top view (left figure) and sectional drawing (right figure) of a mask pattern. The figure which shows the example of the defect of a mask. The figure explaining the method to test | inspect the foreign material on a wafer. The figure which shows the example of the defect of the mask of 6-chip structure. The figure which shows the example of the shot layout of the wafer peripheral part in which both a full field and a partial field exist. The figure which shows the example of the imprint apparatus of a cluster structure. The flowchart of the mask selection control in an imprint process. The flowchart of the mask selection control in an imprint process. The figure explaining the structure of the mask containing the dummy pattern.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment, It shows only the specific example advantageous for implementation of this invention. Moreover, not all combinations of features described in the following embodiments are indispensable for solving the problems of the present invention.

  In the following embodiment, an example of an imprint apparatus using a mask mainly for imprint lithography of a semiconductor element will be described. The imprint method in the embodiment is based on the jet and flash imprint lithography (JFIL) method described above. FIG. 1 is a diagram illustrating a configuration of an imprint apparatus 100 according to the present embodiment. In the present embodiment, the imprint apparatus 100 employs a photocuring method in which the resin is cured by irradiation of ultraviolet rays as a resin (resist) curing method, but is not limited thereto. For example, a thermosetting resist is used. It is also possible to employ a thermosetting method.

  On the mesa (pattern surface) facing the wafer W of the mask M, a product pattern to be transferred to the resist supplied to the wafer W is formed. The product pattern has, for example, a rectangular shape and is made of a mold of a material (such as quartz) that transmits ultraviolet rays. The mask holding unit 101 holds the mask M by vacuum suction force or electrostatic force. The mask holding unit 101 includes a drive mechanism that drives the mask M in the z-axis direction, and presses the product pattern onto the uncured resist applied by the dispenser 105 on the wafer W with an appropriate force. Thereafter, the ultraviolet irradiation unit 102 irradiates ultraviolet rays through the reflection mirror 103 to cure the resist, and then peels (releases) the product pattern from the cured resist on the wafer W. An alignment optical system 106 is disposed in the vicinity of the optical path between the reflection mirror 103 and the mask M. The control unit 110 includes a CPU, a memory, and the like, and controls the operation of each unit of the imprint apparatus 100.

  The wafer W as a substrate includes, for example, a single crystal silicon wafer, an SOI (Silicon on Insulator) wafer, or the like. Wafer stage 104 includes a substrate chuck for holding wafer W and a drive mechanism for aligning the product pattern with the wafer using alignment optical system 106. Such a drive mechanism is composed of, for example, a coarse drive system and a fine drive system, and drives the wafer in the x-axis direction and the y-axis direction.

  The product pattern formed on the mesa (pattern surface) of the mask M is transferred to the wafer W. In a region where the imprint process is performed on the wafer W, fine resist (drop) is dropped from the dispenser 105 in advance. In the imprint sequence, the pattern surface of the mask is brought close to the shot region on the wafer coated with the resist. In this specification, an area that is imprinted collectively is referred to as a “shot area”. Note that each of the plurality of areas that are imprinted together may be a chip area, or may be a shot area. When the dropped resist comes into contact with the pattern surface of the mask, it spreads in the XY direction of the shot region, and draws the mask pattern surface with a capillary force. Thus, a pattern in which the unevenness of the mask is inverted is formed on the wafer.

  Next, the configuration of shots on the mask and wafer will be described. FIG. 2 shows an example of a one-shot product pattern transferred onto a wafer. In this example, the same pattern is arranged for 6 chips, for example. One chip is composed of in-chip patterns (patterns of memory cells, sense amplifiers, peripheral circuits, etc. in memory products) and a scrub line, and an alignment mark and a monitor mark are arranged in the scrub line.

FIG. 3 shows an enlarged configuration of one chip. Usually, an alignment mark and a monitor mark are arranged at four corners adjacent to the chip, and the alignment mark is formed in advance by a prior process, and a necessary film is formed on the mark. The monitor mark is arranged so that the quality of the result of the alignment with the previous process can be understood. That is, by comparing the positions of the mark formed in the imprint process and the mark formed in the previous process, it can be determined whether or not the alignment is within a predetermined accuracy. Furthermore, alignment is required in the next process as in this process. Therefore, in this process, formation of alignment marks necessary for alignment in the next process, and formation of monitor marks to confirm whether the alignment accuracy between the next process and this process satisfies the conditions Is required.
The configuration of the imprint apparatus in this embodiment is generally as described above, and the imprint apparatus 100 has a product pattern related to a product collectively for a plurality of regions on a substrate each corresponding to at least one product. Pattern formation is performed.

  4A is a top view of the mask pattern, and FIGS. 4B and 4C are examples of cross-sectional views. In the top view of (a), an example of a 6-chip configuration is shown as in FIGS. The cross-sectional views of (b) and (c) show the A-A ′ cross section of the top view (a). The mask is composed of a mask substrate and a mesa portion obtained by partially processing the mask substrate, and a fine pattern is drawn on the mesa portion. In the A-A ′ cross section, as described with reference to FIG. 3, one chip is composed of an in-chip pattern and an adjacent scrub line (pattern for forming alignment marks and monitor marks). For this reason, the configuration shown in FIG. The level of miniaturization is generally such that the alignment mark and the monitor mark on the scrub line are relatively narrow (thick) compared to the pattern in the chip.

  FIG. 5 shows an example of a mask defect. FIG. 5 is an enlarged view of the mesa cell pattern in the mask pattern cross-sectional view shown in the lower right diagram of FIG. FIG. 5A shows a normal pattern. FIG. 5B shows clogging in which a part of the cured resin remains on the mask when the mold is peeled off from the cured resin. FIG. 5C shows the damage of the mask pattern caused by particles adhering to the wafer. These mask defects continuously cause transfer defects (repetitive defects) in subsequent shot areas to which imprint processing is performed, and cause defective chips.

Next, specific contents of imprint control by the control unit 110 will be described.
First, it is assumed that the coordinates of the defect existing on the mask have been confirmed in advance by the mask defect inspection. Next, before imprinting, the wafer to be imprinted is inspected at a position on the wafer by a wafer foreign matter inspection apparatus (foreign matter inspection unit). In addition, it is assumed that it is confirmed which No of the shot and the chip to which the imprint corresponds to the imprint.

  The foreign matter inspection on the wafer is performed using laser light by, for example, a wafer foreign matter inspection apparatus. When there is no foreign matter on the wafer, as shown in FIG. 6A, the laser light incident on the wafer is reflected at a reflection angle equal to the incident angle, and is collected in a light receiving detector B provided in advance. Lighted. On the other hand, when a foreign substance is present on the wafer, the disturbance light is reflected from the foreign substance and condensed on the light receiving detectors A and C provided in the vicinity of the light receiving detector B as shown in FIG. Is done. By performing the foreign substance inspection as described above by moving the entire surface of the wafer by X, Y movement and θ rotation of the stage, the position coordinates of the foreign substance on the wafer can be confirmed. It is also possible to classify the size of the foreign matter based on the signal intensity received by the light receiving detector.

  FIG. 7 shows an example of defects in a 6-chip mask. In the left figure (mask A), only the area of chip 3 has no defect, and in the areas of chips 1, 2, 4, 5, and 6, the mask pattern becomes clogged as shown in FIG. A state in which the pattern is missing as shown in FIG. When imprinting is performed using this mask, defects are transferred onto the wafer. In the right figure (mask B), it is shown that there are no defects in the areas of the chips 1, 2, 3, 5, 6 and only the area of the chip 4 has defects. Usually, when imprinting is repeated, the mask tends to be locally damaged. However, discarding expensive masks due to breakage in several places significantly reduces productivity and profitability. Therefore, in this embodiment, a measure that can effectively use a damaged mask is proposed.

  The following describes how to use different masks when imprinting. If it is known that there is no foreign matter in the shot area of the wafer to be imprinted by the wafer foreign matter inspection apparatus, imprinting is performed using a mask without a regular defect. On the other hand, when a foreign matter is detected in a partial region (for example, a region corresponding to the chip 4) by the wafer foreign matter inspection apparatus, imprinting is performed using an irregular mask (mask B in FIG. 7). This non-regular mask is a mold having a pattern different from the product pattern in an area corresponding to the partial area and having a product pattern in other areas. This is because when the imprint is performed with a regular mask, the mesa pattern of the regular mask has a defect as shown in FIG. 5B or 5C, and a common defect is generated in the area of the chip 4 at the subsequent imprint. This is because they may be generated.

  By using different masks in this way, even if a mask pattern is damaged due to foreign matter on the wafer and a new defect is generated in the mask, it only needs to be additionally generated in a chip that is already defective. . Therefore, there is no influence of common defects on subsequent shots.

  Next, an example of using different masks for a shot in a full field where the peripheral area of the wafer is not included in the shot area and a shot in a partial field where the peripheral area of the wafer is included in the shot area is used. Indicates. In the partial field, a part of the product pattern protrudes from the wafer and is not transferred to the wafer. In this specification, this state is referred to as “missing”. In the periphery of the wafer, there is a bulge (convex portion) along the shape of the periphery of the wafer of the adhesion enhancing agent applied to improve the adhesion with the underlying film or resist, and the wafer is at the periphery of the wafer. There is a region where there are more foreign objects than the central part and cannot be detected by a prior foreign object inspection device. Therefore, when imprinting a partial field with a regular mask, there is a high possibility that the mask pattern will be damaged. FIG. 8 shows a shot layout of a wafer peripheral portion where both a full field and a partial field exist. Here, three shots R1C1, R2C1, and R2C2 are full fields, and three shots R1C2, R1C3, and R2C3 are partial fields. If the preliminary inspection shows that there are no foreign objects on the wafer, the imprint is performed using a regular mask for the three full-field shots R1C1, R2C1, and R2C2. On the other hand, the three shots in the R1C2, R1C3, and R2C3 partial fields, as described above, may damage the mask pattern when imprinted with a regular mask. Imprint using a mask.

  In the R1C2 shot of FIG. 8, since the chip 4 is a partial chip that is partly outside the wafer, the mask pattern may be damaged when the chip 4 is imprinted. Therefore, in the R1C2 shot, a mask (mask B in FIG. 7) in which the chip 4 has already been damaged is used. In the R1C3 shot, since the chip other than the chip 3 is a partial chip or a totally invalid chip, only the chip 3 has no problem, and the mask A of FIG. In the above, two examples of masks A and B have been introduced, but this is only an example. For example, if the mask has known effective chips (defect-free chips) and the wafer has known effective chips (chips without foreign matter), the most suitable mask for each shot is used by providing each combination. be able to.

  FIG. 9 shows an example of an imprint apparatus having a configuration including a plurality of imprint units, that is, a cluster structure having a plurality of chambers. FIG. 9 shows a configuration including a wafer foreign matter inspection apparatus in addition to the eight chambers. The wafer foreign matter inspection apparatus is an apparatus as shown in FIG. 6 and is included in this cluster type imprint apparatus. In the following, an example of imprinting with this cluster structure is shown.

  In this case, a plurality of molds having different patterns are stored in the plurality of imprint units. The control unit selects an imprint unit that performs pattern formation from among the plurality of imprint units, based on the received foreign substance information. For example, in Chamber 1, only a shot that has no problem in the foreign matter inspection of the wafer in advance is imprinted, and a mask without a regular defect is applied at that time. Thereafter, for example, in Chamber 2, imprinting is performed only for shots that are known to have foreign objects in shot 4. In Chamber 3, the imprint of the shot in which it is known that only the chip 3 such as R1C3 in FIG. After inspecting the wafer for foreign matter, chamber 1 is imprinted with a full field free of foreign matter and then repeatedly enters a chamber with a suitable mask to imprint shots that have not yet been imprinted. Thus, imprinting on the entire wafer surface is completed. Here, from the viewpoint of productivity, the mask prepared in the chamber is changed so that the number of imprint wafers per unit time is maximized, and a regular mask is prepared in a plurality of chambers if necessary. In addition, when there is no appropriate mask, it is possible to perform imprint with a mask that is close to the optimum as judged from the particle size of the foreign matter inspection.

  FIG. 10 shows a flowchart relating to imprint processing in the present embodiment. After the wafer foreign matter inspection, the processing is divided into a full field shot and a partial field shot. In the case of a full field shot, if no foreign matter is detected from the wafer, the chamber of the regular mask is selected and imprinting is performed. If a foreign object is detected from the wafer, specify the area corresponding to which chip of which shot on the wafer, and an appropriate mask from the pre-registered masks and the mask are prepared. Select the chamber. Then, imprinting is performed using the selected chamber and mask. In the case of a partial field shot, it is possible to specify a region corresponding to which chip of which shot on the wafer, and set a suitable mask from pre-registered masks and a chamber in which the mask is prepared. Select and perform imprinting under that condition.

  Even if a foreign matter inspection of the wafer is performed and measures are taken to prevent damage to the mask, for example, imprinting may be performed with the foreign matter attached after the foreign matter inspection being sandwiched, and the mask pattern may be damaged. Therefore, each time the mask is used, it is necessary to perform a pattern defect inspection by the defect inspection unit, and to correct registration when a new damaged portion is detected. FIG. 11 is a flowchart relating to mask selection control at that time. Based on the mask information registered in advance, the final shot of the wafer imprinted with the mask is compared with the pattern before the final shot to check whether a new common defect has occurred. Here, if there is a pattern defect at the same coordinate of the last shot and the shot before the last shot, it is defined as a common defect. Based on the defect information, the existing common defect is compared with the mask defect information registered in advance, and it is confirmed whether the coordinates match. If they match, there is no need to re-register, but if there is a common defect not previously registered, the mask pattern is inspected by the defect inspection unit after mask cleaning. If there is a defect in the mask that is not registered in advance, re-registration is performed, information on the mask is updated, and preparation for imprinting under appropriate conditions is made after the next time.

  Further, although a damaged mask is used here, it is also possible to reduce the mask cost by making a specific portion a dummy pattern in advance. In FIG. 12, an in-chip pattern of a specific chip (corresponding to the chip 4 in FIG. 3) is created in advance as a dummy pattern. Thereby, the cost required for mask drawing can be reduced. When there is a foreign object on chip 4 in FIG. 3 or when imprinting a partial shot such as R1C2 or R2C3 in FIG. 8, instead of using a mask in which chip 4 is damaged, only chip 4 is used as a dummy pattern. It is also possible to use masks that have been used. However, as shown in FIG. 3, the alignment mark and the monitor mark necessary for the next process must be arranged in the chip 4. Therefore, only the in-chip pattern is used as the dummy pattern, and the pattern in the scrub line needs to be drawn on the mask in the same manner as the regular mask.

  The present invention supplies a program that realizes one or more functions of the above-described embodiments to an imprint apparatus via a network or a storage medium, and one or more processors in a computer in the imprint apparatus read and execute the program This process can be realized. The present invention can also be realized by an external computer connected to the imprint apparatus executing a program that realizes one or more functions described above. For example, such an external computer receives information on the position of a foreign substance on a wafer, or if the shot is a shot having a chip. Then, based on the received information, a command for causing the imprint apparatus to perform the operation of the above embodiment is issued.

<Production method>
The method for manufacturing an article (product) according to an embodiment of the present invention is suitable for manufacturing a product such as a micro or nano device such as a semiconductor device or an element having a fine structure. The manufacturing method includes a step of performing pattern formation on a substrate using an imprint apparatus. Further, the manufacturing method includes other well-known processes (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.) for processing the patterned substrate. sell. 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 as compared with the conventional method.

100: Imprint apparatus, M: Mask, W: Wafer, 102: Ultraviolet irradiation unit, 105: Dispenser

Claims (15)

An imprint apparatus that performs pattern formation with a product pattern related to the product collectively for a plurality of regions on a substrate each corresponding to at least one product,
An imprint unit for forming the pattern;
A control unit for controlling the operation of the imprint unit,
The control unit has a different pattern different from the product pattern in a region corresponding to the partial region when the foreign matter or the chip exists in the partial region of the plurality of regions, and the part An imprint apparatus that controls the operation so that the pattern is formed with a mold having the product pattern in an area corresponding to an area different from the area.   The imprint apparatus according to claim 1, wherein the different pattern includes a pattern in which a defect is generated in the product pattern.   The imprint apparatus according to claim 1, wherein the mold has a pattern for forming a mark on the substrate with respect to the another pattern.   The control unit selects a mold for forming the pattern in the plurality of regions based on information on the foreign matter or chip and information on the different pattern of each mold. 4. The imprint apparatus according to claim 1.   5. The imprint apparatus according to claim 1, wherein each of the plurality of regions is a chip region or a shot region formed on the substrate.   The imprint apparatus according to claim 1, further comprising an inspection unit that inspects the foreign matter on the substrate.   The imprint apparatus according to any one of claims 1 to 6, further comprising an inspection unit that inspects the defect of the mold. Including a plurality of the imprint parts,
The control unit causes the plurality of imprint units to hold a plurality of molds having different regions where the different patterns exist, and based on the information on the foreign matter, the plurality of regions of the plurality of imprint units. The imprint apparatus according to claim 1, wherein an imprint unit that performs the pattern formation is selected. An imprint method in which a plurality of regions on a substrate corresponding to at least one product are collectively formed with a product pattern related to the product,
When a foreign substance or a chip exists in a part of the plurality of regions, the region corresponding to the part of the region has a different pattern different from the product pattern and is different from the part of the region. An imprinting method comprising performing the pattern formation with a mold having the product pattern in an area corresponding to the area.   The imprint method according to claim 9, wherein the different pattern includes a pattern in which a defect is generated in the product pattern.   11. The imprint method according to claim 9, wherein the mold has a pattern for forming a mark on the substrate with respect to the another pattern.   12. The mold according to claim 9, wherein a mold for forming the pattern in the plurality of regions is selected based on information on the foreign matter or chip and information on the different pattern of each mold. 2. The imprint method according to item 1.   The imprint method according to claim 9, wherein each of the plurality of regions is a chip region or a shot region formed on the substrate. A step of performing pattern formation on a substrate using the imprint apparatus according to any one of claims 1 to 8 or the imprint method according to any one of claims 9 to 13,
Processing the substrate on which the pattern has been formed in the step;
A method for producing an article comprising: A program for causing a computer to execute an imprint method for performing pattern formation with a product pattern relating to the product collectively for a plurality of regions on a substrate corresponding to at least one product,
The imprint method is:
When a foreign substance or a chip exists in a part of the plurality of regions, the region corresponding to the part of the region has a different pattern different from the product pattern and is different from the part of the region. Performing the pattern formation with a mold having the product pattern in a region corresponding to the region;
A program characterized by that.

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