JP6071263B2 - Exposure apparatus, exposure system, and device manufacturing method using the same - Google Patents

Description

  The present invention relates to an exposure apparatus and an exposure system, and a device manufacturing method using them.

  In a lithography process included in a manufacturing process of a semiconductor device, a liquid crystal display device, or the like, an exposure apparatus applies a pattern of an original (such as a mask) to a photosensitive substrate (a wafer having a resist layer formed on the surface) via a projection optical system. Or a glass plate). In such an exposure apparatus, due to changes in the surface shape of the substrate due to various factors, a focus shift (shift in the focus position of the projection optical system) occurs in the pattern image to be imaged on the substrate surface. There is a case. In order to cope with this focus shift, the conventional exposure apparatus, for example, measures the surface shape of the substrate in advance in units of substrates or lots, and focuses on the surface shape of the same tendency specified from the measurement result. Some perform corrections. With respect to this focus correction, Patent Document 1 discloses a surface position detection method that measures the amount of change in the surface position while moving the substrate stage along the track along the surface shape of the substrate, and drives the amount of change from the track. . However, the undulation shape of the substrate surface varies from substrate to substrate due to differences in substrate manufacturing methods and manufacturers. Therefore, if different substrates from different manufacturers are mixed in the same lot processed by the exposure equipment, the surface shape of the measured substrate and the surface shape of the substrate to be corrected are different, so an accurate correction result may not be obtained. is there. Therefore, if focus correction is strictly performed, a new shape measurement is performed on a substrate having a different surface shape to be processed, or a shape measurement is performed on all the substrates. It is necessary to perform correction based on the above.

JP 2010-258085 A

  However, it will take more time to correct the focus shift when judging the characteristics of each board as described above and newly performing shape measurement or performing shape measurement on all the boards. This is not desirable from the viewpoint of the throughput of the exposure apparatus.

  The present invention has been made in view of such a situation, and an object thereof is to provide an exposure apparatus that is advantageous in, for example, suppressing a correction time for defocusing due to a change in the surface shape of a substrate.

In order to solve the above problems, the present invention is an exposure apparatus that irradiates a pattern formed on an original plate with light from an illumination optical system, and exposes an image of the pattern on a substrate via a projection optical system, A substrate stage that holds and moves the substrate, a measurement unit that obtains the surface shape of the substrate by measuring the height of the surface of the substrate placed on the substrate stage, and a second layer formed on the substrate. the first height of the surface of the layer and controls the exposure of the second layer by correcting the focus direction position of the base plate using surface shape data obtained by measuring using the measurement unit, the exposure process of And a control unit that causes the measurement unit to measure the height of the surface of the second layer in parallel with the control of the above, and information on the height of the surface of the second layer measured by the measurement unit is the exposure of the second layer It is not used for correcting the focus direction position of the substrate in processing, but is formed on the second layer. Used to correct the focus direction position of the substrate in the exposure processing of the third layer that.

  According to the present invention, for example, it is possible to provide an exposure apparatus that is advantageous for suppressing the correction time of focus shift caused by a change in the surface shape of a substrate.

It is a figure which shows the structure of the exposure apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the exposure process sequence which concerns on one Embodiment. It is a figure which shows the structure of the exposure system which concerns on one Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(Exposure device and exposure system)
First, an exposure apparatus according to an embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing a configuration of an exposure apparatus 1 according to the present embodiment. The exposure apparatus 1 is used for manufacturing a liquid crystal display device as an example, and a pattern (for example, a circuit pattern) formed on a mask (original plate) 2 by a step-and-scan method is applied on a glass plate 3 (on a substrate). A scanning projection exposure apparatus for transferring and exposing to the above. In FIG. 1, the Z axis is taken in parallel to the optical axis of the projection optical system 4, and the Y axis is taken in the scanning direction of the mask 2 and the glass plate 3 during exposure in a plane perpendicular to the Z axis. The X axis is taken in the non-scanning direction orthogonal to the axis. The exposure apparatus 1 includes an illumination optical system 5, a mask stage 6, a projection optical system 4, a substrate stage 7, a substrate shape measuring unit 8, and a control unit 9. The illumination optical system 5 has a light source such as an Hg lamp, for example, and irradiates the mask 2 with illumination light 10 shaped like a slit. The mask stage 6 is movable while holding the mask 2 and moves relatively in synchronization with the movement of the substrate stage 7 during scanning exposure. The projection optical system 4 projects and forms exposure light (pattern image) 11 from the mask 2 on the surface of the glass plate 3 held on the substrate stage 7. Although not shown, the projection optical system 4 is an Offner optical system composed of, for example, a plane mirror, a concave mirror, and a convex mirror.

  In particular, the substrate stage 7 moves in the optical axis direction (Z-axis direction) of the projection optical system 4 and the XY plane direction orthogonal to the optical axis while holding the glass plate 3 coated with the photosensitive agent. Further, the substrate stage 7 includes a plurality of reference mirrors 12 corresponding to at least the XYZ axial directions on the side surface thereof. The exposure apparatus 1 includes a plurality of laser interferometers 13 that measure the position of the substrate stage 7 by irradiating these reference mirrors 12 with a beam such as helium neon. The set of the reference mirror 12 and the laser interferometer 13 constitutes a position measurement unit, and FIG. 1 shows only one set as an example. The laser interferometer 13 measures the position of the substrate stage 7 in real time and transmits the measured value to the control unit 9. The position measuring unit is not limited to the interferometer as described above, and an encoder using a semiconductor laser can also be used.

  The substrate shape measuring unit (measuring unit) 8 measures the shape of the surface of the glass plate 3 such as the undulation of the surface of the glass plate 3, and is specifically placed on the substrate stage 7. The height position (surface height) of the surface of the glass plate 3 in the Z-axis direction is detected. As this board | substrate shape measurement part 8, a laser interferometer is employable, for example.

  The control unit 9 is configured by, for example, a computer, and is connected to each component of the exposure apparatus 1 via wiring, and can execute the operation and control of each component according to a program or the like. In particular, the control unit 9 of this embodiment includes at least a stage control unit 14 that controls the operation of the substrate stage 7, a substrate information management unit 15, a substrate information storage unit 16, and a main control unit 17. The stage control unit 14 controls the operation of the substrate stage 7 at the time of scanning exposure based on the drive command from the main control unit 17 and also controls the operation of the substrate stage 7 in the Z-axis direction at the time of focus correction described later. . The substrate information management unit (management unit) 15 acquires substrate identification information and processing layer information from the external system control unit 100 that controls the operation of the exposure apparatus 1 from the outside, particularly when the glass plate 3 is carried in. Here, the external system control unit 100 includes at least one exposure apparatus including the exposure apparatus 1 installed on the same floor, and assigns a processing substrate to each exposure apparatus in each exposure system connected by a network line. It controls and controls. “Substrate identification information” is uniquely determined by all apparatuses (exposure apparatus, coating and developing apparatus, etc.) that process a substrate (here, the glass plate 3), and manages unique information for each substrate. Information used to do this. Furthermore, “processing layer information” refers to what layer processing this time corresponds to when processing a plurality of exposure processes on a single substrate and overlaying pattern layers, that is, within the exposure apparatus. This is information indicating how many layers of patterns have already been formed on the carried substrate. The board identification information and the processing layer information are managed by the external system control unit 100. Further, the substrate information management unit 15 refers to the acquired substrate identification information and processing layer information, and acquires the surface shape data (substrate shape data) of the substrate when an arbitrary layer is formed from the substrate information storage unit 16. Then, the acquired substrate shape data is transmitted to the main controller 17 during the exposure process. Further, the substrate information management unit 15 acquires the height position information detected during the exposure process from the substrate shape measurement unit 8, and the detection time of the substrate shape measurement unit 8 from the laser interferometer 13 of the position measurement unit. The position information of the XY plane at is acquired. The substrate information storage unit (storage unit) 16 is a storage medium such as an SSD or HDD that temporarily stores substrate shape data. The board shape data stored in the board information storage unit 16 is obtained by associating the height position information acquired by the board information management unit 15 and the position information on the XY plane in advance. The main control unit 17 transmits a drive command to the stage control unit 14 based on the substrate shape data received from the substrate information management unit 15, and transmits a drive command related to the exposure process to each component.

  Next, the flow of exposure processing by the exposure apparatus 1 will be described. FIG. 2 is a flowchart showing an exposure processing sequence in the exposure apparatus 1. In the flowchart of FIG. 2, the exposure apparatus 1 constitutes an exposure system as at least one of a plurality of exposure apparatuses, and a glass plate 3 to be processed is placed in the exposure apparatus 1 according to a command from the external system control unit 100. It is assumed that it will be brought in. Furthermore, the exposure system shall transfer the pattern which consists of a several layer with respect to the one glass plate 3 by overlapping a multiple times of exposure process. In addition, in the following description, as an example, the pattern of up to the second layer has already been transferred onto the glass plate 3 to be processed this time that has been carried into the exposure apparatus 1. It is assumed that the third layer pattern is transferred by the processing.

  First, when the exposure processing sequence is started, the main control unit 17 loads the glass plate 3 into the exposure apparatus 1 based on a substrate loading command from the external system control unit 100 (step S100: substrate loading). Next, in accordance with the loading of the glass plate 3 in step S100, the substrate information management unit 15 acquires substrate identification information and processing layer information from the external system control unit 100 (step S101). At this time, the processing layer information includes information that the current exposure processing corresponds to the pattern transfer of the third layer of the uppermost layer (the pattern up to the second layer has already been transferred under the uppermost layer). include. Next, the substrate information management unit 15 refers to the acquired substrate identification information and layer information, and acquires (extracts) substrate surface shape data from the substrate information storage unit 16 (step S102). At this time, the acquired surface shape data is for the glass plate 3 to be processed this time specified by the substrate identification information, and the pattern up to the second layer below the uppermost layer is transferred. It is the data which shows the surface shape of the board | substrate in the time of being.

  Next, the main control unit 17 executes the following steps in parallel. First, the main control unit 17 causes the substrate stage 7 to correct the position in the focus direction of the projection optical system based on the surface shape data of the substrate extracted by the substrate information management unit 15, and then causes each component to Then, an exposure process is performed (step S103). At this time, at the time of focus correction, the main control unit 17 transmits the surface shape data of the substrate to the stage control unit 14, and appropriately drives the substrate stage 7 in the Z-axis direction as described above to obtain the surface shape of the substrate. Correct the resulting focus shift. Here, “because of the surface shape of the substrate” means that the height position of the surface of the glass plate 3 varies depending on the point due to, for example, the undulation of the glass plate 3. On the other hand, the correction of the focus position refers to correction so that the focus position (focus position) of the projection optical system matches the height position. On the other hand, in parallel with step S103, the main control unit 17 causes the substrate shape measurement unit 8 to detect the height position of the surface of the glass plate 3 in a state where the third layer pattern is transferred (step). S104).

  Next, the substrate information management unit 15 acquires the height position information detected in step S104, the surface shape data obtained from the height position information and the position information of the substrate stage 7, and the substrate identification information. And the processing layer information are associated (step S105). At this time, the processing layer information includes information indicating that the surface shape data is obtained when the third layer pattern has been transferred. Thereafter, the board information management unit 15 stores the associated information in the board information storage unit 16. Then, after the transfer of the third layer pattern to the glass plate 3 is completed, the main control unit 17 carries out the processed glass plate 3 to the outside of the exposure apparatus 1 (step S106), and ends a series of exposure processes. .

  As described above, the exposure apparatus 1 measures the shape of the glass plate 3 for each exposure process, and performs focus correction with reference to the next (next layer) pattern transfer to the same glass plate 3. Perform an exposure process. Thereby, the exposure apparatus 1 can appropriately perform the focus correction before the exposure process and perform the pattern transfer with high accuracy even when the focus shift due to the change in the shape of the glass plate 3 may occur. . Since the uppermost layer is formed by applying a resist or the like almost uniformly on the surface of the lower layer, the surface shape of the uppermost layer and the surface shape of the lower layer have the same tendency. Therefore, there is no problem even if the focus direction position is corrected with respect to the surface of the uppermost layer using the surface shape data of the lower layer. Further, the exposure apparatus 1 measures the shape of the glass plate 3 in parallel during focus correction or exposure processing. That is, since a single measurement time for measuring the shape of the glass plate 3 is not provided in a series of exposure processing times, an increase in time for focus correction is consequently suppressed. Therefore, the influence on the throughput of the exposure apparatus 1 can be suppressed as much as possible.

  Note that the surface shape data relating to the second layer extracted by the substrate information management unit 15 in step S102 is the height measured during the previous exposure process by the exposure apparatus 1 with reference to steps S104 and S105. It is based on position information. Here, for example, when the current exposure processing is related to pattern transfer of the first layer, there may be no surface shape data to be referred to. In this case, the exposure apparatus 1 may not perform the focus correction in step S103, but simply perform the height position detection in step S104 to create surface shape data to be referred to next time.

  In the above exposure processing sequence, the flow of the substrate surface shape data and the like is exemplified as the operation for one exposure apparatus 1 included in the exposure system. On the other hand, for example, other exposure apparatuses included in the exposure system have the same configuration and control as the exposure apparatus 1 so that the surface shape data is shared with a plurality of other exposure apparatuses via the external system control unit 100. You may let them. Further, in the present embodiment, the substrate information management unit 15 and the substrate information storage unit 16 are configured in the exposure apparatus 1, but are not installed in the exposure apparatus 1 which is one exposure apparatus in the exposure system. There may be a configuration in which the exposure system is installed, for example, in an external system control unit. FIG. 3 is a schematic diagram showing a configuration of an exposure system 200 including three exposure apparatuses 201, 202, and 203 as an example, and a system control unit 205 connected to each of the exposure apparatuses 201 to 203 via a network line 204. is there. Among these, the system control unit 205 includes a board information management unit 206 and a board information storage unit 207 corresponding to the board information management unit 15 and the board information storage unit 16, respectively. In this case, the height position information and the like of the glass plate 3 obtained by measuring in a plurality of exposure apparatuses are once collected in the system control unit 205. Then, when the next exposure process is performed in each exposure apparatus, the system control unit 205 obtains the surface obtained by referring to the height position information together with the substrate identification information and the processing layer information. The shape data is transmitted to each exposure apparatus.

  As described above, according to the present embodiment, it is possible to provide an exposure apparatus that is advantageous for suppressing the correction time for defocusing due to a change in the surface shape of the substrate. Further, by including such an exposure apparatus, it is possible to provide an exposure system that is advantageous for transferring a good pattern to the substrate while suppressing the influence on the throughput.

(Device manufacturing method)
Next, a method for manufacturing a device (semiconductor device, liquid crystal display device, etc.) according to an embodiment of the present invention will be described. A semiconductor device is manufactured through a pre-process for producing an integrated circuit on a wafer and a post-process for completing an integrated circuit chip on the wafer produced in the pre-process as a product. The pre-process includes a step of exposing a wafer coated with a photosensitive agent using the above-described exposure apparatus, and a step of developing the wafer. The post-process includes an assembly process (dicing and bonding) and a packaging process (encapsulation). A liquid crystal display device is manufactured through a process of forming a transparent electrode. The step of forming the transparent electrode includes a step of applying a photosensitive agent to a glass substrate on which a transparent conductive film is deposited, a step of exposing the glass substrate on which the photosensitive agent is applied using the above-described exposure apparatus, and a glass substrate. The process of developing is included. According to the device manufacturing method of the present embodiment, it is possible to manufacture a higher quality device than before.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Exposure apparatus 2 Mask 3 Glass plate 4 Projection optical system 5 Illumination optical system 7 Substrate stage 8 Substrate shape measurement part 9 Control part

Claims (7)

An exposure apparatus that irradiates a pattern formed on an original plate with light from an illumination optical system and exposes an image of the pattern on a substrate through a projection optical system,
A substrate stage for holding and moving the substrate;
A measurement unit that measures the height of the surface of the substrate placed on the substrate stage and acquires the surface shape of the substrate;
Using surface shape data obtained the height of the surface of the first layer below the second layer formed on the substrate is measured by using the measurement unit to correct the focus direction position of the base plate before SL and controls the exposure of the second layer, the control unit for measuring the height of the front Symbol surface of the second layer in the measurement unit in parallel with control of the exposure process Te,
Equipped with a,
The information on the height of the surface of the second layer measured by the measurement unit is not used for correcting the focus direction position of the substrate in the exposure processing of the second layer, and is formed on the second layer. An exposure apparatus used for correcting the position of the substrate in the focus direction in the third layer exposure process .   The control unit includes substrate identification information for identifying the substrate, and processing layer information indicating how many layers the pattern has already been transferred on the substrate to the exposure apparatus. An arbitrary layer is obtained by associating the measurement value measured in the previous exposure process by the measurement unit with the substrate identification information and the processing layer information, obtained from a system control unit that controls and controls the assignment of the substrate from the outside. 2. The exposure apparatus according to claim 1, wherein the surface shape data is acquired. The control unit executes the acquisition of the substrate identification information and the processing layer information from the system control unit, and the acquisition of the measurement value from the measurement unit, and manages the surface shape data,
A storage unit for storing the surface shape data managed by the management unit;
The exposure apparatus according to claim 2, comprising:   4. The control unit according to claim 1, wherein the control unit does not perform the correction of the focus direction position when the surface shape data to be referred to does not exist in advance during the exposure process. 5. The exposure apparatus described. The control unit controls the exposure process using surface shape data obtained by measuring the surface height of the layer one layer below the second layer using the measurement unit. The exposure apparatus according to any one of claims 1 to 4. A step of exposing a substrate using the exposure apparatus according to claim 1;
Developing the exposed substrate;
A device manufacturing method comprising: An exposure method for irradiating a pattern formed on an original plate with light from an illumination optical system and exposing an image of the pattern on a substrate through a projection optical system,
Measuring the height of the surface of the first layer formed on the substrate to obtain surface shape data;
A control step of controlling the exposure process of the second layer by correcting the position in the focus direction of the substrate on which the second layer is formed after the first layer is formed using the acquired surface shape data When,
In parallel with the control step, measuring the height of the surface of the second layer,
The measured information on the height of the surface of the second layer is not used for correcting the focus direction position of the substrate on which the second layer is formed after the first layer is formed. An exposure method, wherein the exposure method is used for correcting a focus direction position of the substrate in the exposure processing of the substrate on which the third layer is formed after two layers are formed.

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