JP2005064139A - Substrate holding device and exposure device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it easy to deliver a substrate between an alignment station and an exposure station without complicating the structure of a device. <P>SOLUTION: The substrate holding device sucks and holds a substrate 2 by a negative pressure, and it is provided with a main body 3, a suction hole 37 that is formed in the main body 3 to suck an open air, and a first hollow part 35 that is formed inside the main body 3 and is communicated with the suction hole 37. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a substrate holding apparatus that sucks and holds a substrate as a workpiece.

  An exposure process, which is one of the manufacturing processes of a semiconductor device, involves projecting and exposing a pattern of an original plate onto a substrate to be exposed via a projection optical system, and is generally manufactured by superposing a plurality of patterns.

  At this time, alignment marks for aligning the relative positions of the original plate and the substrate are measured by an alignment scope provided in the exposure apparatus, so that the original plate and the substrate are aligned, so-called alignment.

  For this alignment, a die-by-die alignment method is performed for each shot, which is exposed multiple times on the substrate, and alignment is performed with one or more representative shots. Positioning includes global alignment which is performed by interpolating from measurement values obtained when alignment is performed with representative shots.

In general, global alignment is performed by optimizing selection of representative shots on the substrate from the viewpoint of improving the throughput of the apparatus.
Japanese Patent Laid-Open No. 1-49007

  However, the alignment accuracy required for recent semiconductor exposure apparatuses is becoming stricter, and further higher accuracy is required.

  In particular, in the process of manufacturing semiconductor devices, the substrate undergoes expansion and contraction and deformation due to various processes applied to the substrate, and even if the substrate is positioned by global alignment, alignment is performed with the accuracy required for all shots. In some cases, it is not possible to perform the exposure.

  In order to perform exposure that is not affected by expansion / contraction or deformation of the substrate, the number of locations on the substrate to be aligned is increased. Ultimately, if all shots are aligned, errors due to global alignment interpolation can be avoided. This results in die-by-die alignment, and the advantage of global alignment that increases the throughput cannot be obtained. In other words, alignment accuracy and throughput must be contradictory.

  As means for solving this problem, in Japanese Patent Laid-Open No. 1-44907 (Patent Document 1), an alignment station that measures a relative position between an alignment mark on a substrate and a reference mark on a substrate holding device, and measurement by the alignment station are performed. There has been proposed a method of providing an exposure station for performing exposure based on the positional information of the alignment mark thus prepared, and achieving both improvement in alignment accuracy and improvement in throughput.

  However, in this method, it is necessary to transfer the substrate holding device while holding the substrate between the alignment station and the exposure station. In the case of so-called vacuum suction in which the substrate is attracted by negative pressure, the substrate holding device is delivered while dragging a pipe for supplying the negative pressure. In other words, whether the piping is routed regardless of whether the substrate holding device is mounted at either the alignment station or the exposure station, or a mechanism for removing the pipe from the substrate holding device and collecting it after the delivery of the substrate holding device is completed. Is necessary, which becomes a factor that complicates the apparatus.

  The present invention has been made in view of the above problems, and an object thereof is to enable transfer of a substrate between an alignment station and an exposure station without complicating the apparatus.

  In order to solve the above-described problems and achieve the object, a substrate holding device according to the present invention is a substrate holding device that holds a substrate by suction under a negative pressure, and includes a main body portion and an outside air formed in the main body portion. And a first hollow portion formed in the main body portion and communicating with the suction hole.

  The substrate holding apparatus according to the present invention is characterized in that a second hollow portion formed by a wall portion formed so as to surround the suction hole and the substrate is provided on an outer surface of the main body portion.

  The substrate holding apparatus according to the present invention is characterized in that a plurality of the second hollow portions are provided, and the plurality of second hollow portions are pressure independent from each other.

  The substrate holding apparatus according to the present invention further includes an on-off valve that opens and closes the first hollow portion.

  In the substrate holding apparatus according to the present invention, a plurality of the first hollow parts are provided in the main body part in a state of being separated by a partition, and the plurality of first hollow parts are selected for the partition. A hole for communication is formed.

  Further, in the substrate holding apparatus according to the present invention, the substrate holding apparatus is used in an exposure apparatus that exposes the pattern of the original plate on the substrate while relatively scanning the substrate and the original plate, and the first hollow portion. Are formed in a lattice shape that is parallel and orthogonal to the scanning direction of the substrate, and the interval between the adjacent partition walls in the scanning direction is equal to the interval in the direction orthogonal to the scanning direction. It is characterized by being set small.

  Further, in the substrate holding apparatus according to the present invention, the first hollow portion has a distance to the surface of the main body portion that sucks and holds the substrate equal to the distance to the surface on the opposite side of the main body portion, It is arrange | positioned in the position which becomes large, It is characterized by the above-mentioned.

  In the substrate holding apparatus according to the present invention, the substrate holding apparatus is used in an exposure apparatus that exposes a pattern of an original on the substrate, and the main body portion is an alignment mark for positioning a relative position with the original. It is characterized by having.

  An exposure apparatus according to the present invention includes an alignment station that measures relative positions of the plurality of exposure areas on the substrate with respect to the alignment marks, and a relative position of the plurality of exposure areas measured by the alignment station with respect to the alignment marks. An exposure apparatus comprising an exposure station that exposes the substrate based on position information, wherein the substrate is sucked and held by the substrate holding device between the alignment station and the exposure station. It is characterized by delivering the substrate.

  According to the present invention configured as described above, the substrate can be transferred between the alignment station and the exposure station without complicating the apparatus.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an exposure apparatus having an alignment station and an exposure station.

  In FIG. 1, reference numeral 1 denotes an alignment station, a shot alignment optical system for measuring the positional relationship between a chuck mark and a shot mark, which will be described later, 2 a substrate, 3 a substrate holding device for holding the substrate 2 by negative pressure suction, 4 This is a substrate stage for moving the substrate 2 together with the substrate holding device 3. Reference numeral 5 denotes a projection optical system that projects an image of the original plate 6 onto the substrate 2, 7 denotes a chuck alignment optical system that aligns the substrate 2 and the original plate 6 at an exposure station, and 8 denotes an illumination optical system.

  The chuck alignment optical system 7 includes the original plate 6 such as a through-the-lens method that detects marks on the substrate 2 and the original plate 6 via the projection optical system 5, and an off-axis alignment method that uses an alignment scope independent of the projection optical system. Any method may be used as long as the relative position of the substrate 2 can be adjusted. Reference numeral 9 denotes a central processing unit (CPU).

  Reference numeral 10 denotes an oblique incident light detection type focus / tilt detector. Reference numerals 11, 12 and 13 denote exposure stations which are connected online with the substrate supply devices 21 and 22 via the CPU 9. Substrate is automatically supplied to these exposure stations sequentially, and exposure processing is performed in full auto. Reference numerals 21 and 22 denote substrate supply apparatuses (hereinafter referred to as alignment stations) for supplying substrates to the exposure stations 11 to 13.

  FIG. 2 is a top view showing a state in which the substrate is attracted to the substrate holding device 3. Parts common or corresponding to those in FIG. 1 are denoted by the same reference numerals.

  Reference numeral 31 denotes a mark (hereinafter referred to as a chuck mark) previously arranged on the substrate holding device 3, and reference numeral 32 denotes an alignment mark (hereinafter referred to as a shot mark) for detecting the position of an exposure region (hereinafter referred to as a shot).

  In FIG. 2, the substrate 2 is adsorbed to the substrate holding device 3 by negative pressure suction. Accordingly, the substrate holding device can be moved in a state where the substrate 2 is placed on the substrate holding device 3, that is, without moving the substrate 2 with respect to the substrate holding device 3.

  In Japanese Patent Laid-Open No. 1-49007, in the case of holding by negative pressure suction, it is described that a pipe for applying a negative pressure can be moved while being attached to a substrate holding device, but in this embodiment, In order to maintain the negative pressure by the suction region formed by the substrate 2 and the substrate holding device 3 and the hollow region that the substrate holding device 3 has, the negative pressure is continuously applied from the outside. It is possible to continue holding the substrate.

  Next, the operation of this embodiment will be described with reference to FIG. 1 and FIG. Here, a case where the substrate 2 is supplied from the alignment station 21 to the exposure apparatus 11 will be described.

  In the alignment station 21, first, the relative position of each shot of the substrate 2 with respect to the check mark 31 is detected by observing the check mark 31 and the shot mark 32 with the shot alignment optical system 1. The check mark 31 serves as a reference mark for aligning the substrate 2 with the original plate 6 at the time of exposure, and thus functions in the same manner as a shot mark of a representative shot on the substrate in conventional global alignment. That is, by detecting the relative position of each shot with respect to the chuck mark 31 in the alignment station, the position of each shot obtained by interpolation from the detected value of the representative shot position is actually measured during exposure by the conventional global alignment. Will be. By this measurement, the amount of deviation from the “positioning target value” of each shot due to the expansion / contraction, deformation, etc. of the substrate during the manufacturing process can be found. The measured deviation amount for each shot is stored in a storage device (not shown) provided in the CPU 9.

  Next, the substrate holding device 3 on which the substrate 2 is placed is moved from the alignment station 21 to the substrate stage 4 ′ of the exposure station 11. The CPU 9 takes out the deviation amount from the “positioning target value” of each shot acquired and stored by the measurement at the alignment station 21 and sends the data to the exposure station 11. In the exposure station 11, the original plate 6 and the check mark 31 are aligned by the chuck alignment optical system 7, and the substrate 2 is moved from the aligned position by the substrate stage 4 ′ by “positioning target value” + “deviation amount” for each shot. Move to perform exposure.

  As described above, using the alignment station, a large number of substrate holding devices 3 are prepared in advance, and each shot position is detected and recorded on the substrate 2 on each substrate holding device 3. The alignment time is substantially only the time for detecting the chuck mark 31 by the chuck alignment system 7. Therefore, high-speed and high-precision alignment is possible on the exposure stage.

  When the processing time for detecting and storing the positions of a plurality of marks on the substrate in the alignment station is shorter than the processing for exposing one exposure area in the exposure station, the throughput caused by delaying the loading of the substrate from the alignment station The substrate can be supplied fully automatically to a large number of exposure stations with one alignment station.

  In FIG. 1, a state in which the substrate is transferred together with the substrate holding device from one alignment station 21 to the plurality of exposure stations 11 to 13 is indicated by arrows.

  In the alignment station, by using a light source of multiple wavelengths for the alignment scope used when detecting the position of each shot mark, the detection rate of marks for alignment (chuck mark 31 and shot mark 32) is improved, More accurate alignment can be performed.

  Further, in order to increase the reproducibility of position detection at the time of alignment, it is necessary to take in more signals and average them. However, the more times the signal is captured, the longer it takes. In the present embodiment, the process of measuring the position of each shot on the substrate 2 with the check mark 31 as a reference by off-axis and the process of performing exposure to transfer the pattern of the original plate can be performed simultaneously. Therefore, a number of alignment stations are provided for each exposure system so that each shot position can be measured for a large number of substrates in advance before the exposure is started. In the exposure station, the chuck mark and the original plate are chuck aligned. After alignment with the optical system, exposure can be performed immediately. That is, it takes no time for the measurement at the alignment station to delay the loading of the substrate into the exposure station, thereby reducing the throughput of the exposure process. Therefore, even if data is taken many times in order to increase accuracy, the throughput is not reduced. This is the same not only for the throughput but also for the detection rate, and more accurate alignment can be performed by taking data many times.

  In particular, in the present embodiment, when the substrate holding device is transferred between the alignment station and the exposure station, the suction region formed by the substrate 2 and the substrate holding device 3 and the substrate holding device 3 are included therein. Since the negative pressure is maintained by the hollow region, it is possible to continue to hold the substrate 2 without receiving continuous negative pressure from the outside. For this reason, a pipe that can be drawn is formed regardless of whether the substrate holding device 3 is in the alignment station or the exposure station, or after the delivery of the substrate holding device 3 is completed, the pipe is removed from the substrate holding device 3. Therefore, it is not necessary to provide a mechanism for collecting the pipe at a position before the substrate holding apparatus is delivered, and an exposure apparatus that cooperates the alignment station and the exposure station with a simple configuration can be provided.

  Next, a specific structure of the substrate holding device in the present embodiment will be described.

  FIG. 3 is a cross-sectional view of the substrate holding device 3, wherein 33 is a suction region formed by the substrate 2 and the substrate holding device 3, 34 is the suction region, and is further divided into a plurality of pressure-independent regions. It is an edge bank.

  Reference numeral 35 denotes a hollow region provided in the substrate holding device, and 36 denotes a partition wall that divides the hollow region 35 into a plurality of regions. Further, the hollow region 35 and the suction region 33 are connected in pressure by the hole 37.

  Further, the partition wall 36 is provided with a hole 38, and the adjacent hollow regions 35 are pressure-conductive through the hole. The holes 38 are selectively formed so as to maintain the pressure independence in the plurality of suction regions 33.

  Reference numeral 39 denotes a valve. When a negative pressure is applied from the substrate stage 4, the valve 39 is opened. After a negative pressure sufficient to hold the substrate 2 is applied, the valve 39 is closed. It has become. Thus, when the substrate holding device 3 is transferred between the alignment station and the exposure station, it can be performed in a state where the pipe for applying the negative pressure is removed. At least one valve 39 is arranged for each of a plurality of pressure-independent negative pressure regions formed by the plurality of adsorption regions 33 and the plurality of hollow regions 35.

  By providing a plurality of pressure-independent negative pressure regions, for example, when a portion where the airtightness of the contact portion between the substrate 2 and the substrate holding device 3 cannot be maintained occurs during the transfer operation of the substrate holding device, the remaining area remains. Therefore, the reliability of the delivery operation of the substrate holding device 3 when the warped substrate is sucked and held can be improved.

  In the substrate holding device 3 of the present embodiment, the chuck mark 31 is provided outside the region where the substrate 2 is held by suction. By enlarging the hollow region 35 not only in the range overlapping with the suction region 33 but also in the range overlapping with the chuck mark 31, it is possible to secure the volume of the hollow region 35 and improve the reliability of suction holding of the substrate. is there.

  The hollow region 35 is preferably disposed at a position where the distance to the surface of the substrate holding device 3 that holds the substrate 2 by suction is equal to or larger than the distance to the opposite surface of the substrate holding device 3. . When a negative pressure is applied to the hollow region, the substrate holding device is deformed due to the influence of atmospheric pressure. By arranging the hollow region 35 in this manner, the deformation of the surface that holds the substrate 2 by suction is minimized. It is possible to reduce the influence on the flattening of the substrate 2.

  In particular, when the substrate holding apparatus of the present embodiment is applied to a scanning exposure apparatus, the partition 36 is arranged in a lattice shape parallel to and orthogonal to the direction in which the substrate holding apparatus is scanned as shown in FIG. Is preferred. In this case, it is preferable to arrange the adjacent partition walls so that the interval in the scanning direction is equal to or smaller than the interval in the direction orthogonal to the scanning direction.

  In scanning exposure, a rectangular exposure irradiation region that is short in the scanning direction of the substrate and long in the direction orthogonal to the scanning direction is formed, and the substrate is driven so that the exposure scanning region is scanned. At this time, measurement is performed immediately before the exposure irradiation area by the focus / tilt detection unit of the oblique incident light detection method, and exposure is performed while sequentially driving the focus direction and the blur direction of the substrate based on the measurement values.

  In this driving method, exposure is performed while sequentially correcting the waviness of the exposed surface of the substrate caused by unevenness of the substrate thickness, etc., so the flatness of the exposed surface of the substrate is in an area equivalent to an arbitrary exposure irradiation region. It only has to be within the desired value.

  The above condition means that in the substrate holding device, the flatness of the substrate suction surface traced in the direction orthogonal to the scanning direction can be required. In order to achieve this, the arrangement of the partition walls 36 separating the hollow regions 35 is preferably provided in a lattice shape parallel to and orthogonal to the direction in which the substrate holding device is scanned, and the distance between the adjacent partition walls 36 in the scanning direction is preferably set. It is preferable that the distance is equal to or smaller than the interval in the direction orthogonal to the scanning direction.

  Further, the partition wall 36 is not limited to a lattice shape that forms a square hollow region as long as the substrate holding device 3 has sufficient rigidity to perform flattening of the substrate with necessary accuracy. Alternatively, as shown in FIGS. 5 (a) to 5 (c), they may be arranged in a space forming a hollow region such as a triangle or a hexagon, or in a combination of concentric and radial partitions.

  As described above, according to the present embodiment, after the alignment information of the shots on the substrate is obtained in advance using the check mark and the original plate and the substrate holding device are aligned, based on the arrangement information obtained in advance. In an exposure apparatus that cooperates with the alignment station and exposure station to control the step movement of the substrate holding apparatus, transfer the substrate holding apparatus between the alignment station and the exposure station, and apply negative pressure to hold the substrate by suction. Since it is possible to carry out without connecting the piping to be applied, it is possible to configure an exposure apparatus that achieves both improved alignment and focus accuracy and improved throughput with a simple mechanism.

  As described above, the substrate holding device of the present embodiment has one or a plurality of hollow regions therein, and the hollow regions are pressure-conductive to the adsorption region of the substrate holding device. It is characterized by that. The suction region referred to here is a so-called vacuum suction type substrate that sucks and holds the substrate by negative pressure suction, and is substantially the same as the outside air formed by the substrate holding device and the substrate held by the substrate holding device. This is a space in which airtightness is maintained and a negative pressure is applied for adsorbing and holding the substrate.

  In the substrate holding device of the present embodiment, a plurality of the hollow regions are provided by partition walls, and the adjacent hollow regions sandwiching the partition walls are electrically connected to each other by holes provided in the partition walls. It is preferable to have

  In the substrate holding apparatus according to the present embodiment, it is preferable that a plurality of the adsorption regions are provided, and the plurality of adsorption regions are pressure independent from each other.

  Further, the plurality of adsorption regions are in pressure communication with the plurality of hollow regions, and the holes of the partition walls are selectively provided so as to keep the pressure independence of the plurality of adsorption regions. It is characterized by.

  In the substrate holding device of the present embodiment, the hollow region may be disposed at a position where the distance to the surface that holds the substrate by suction is equal to or larger than the distance to the opposite surface of the substrate holding device. desirable.

  The substrate holding device of the present embodiment is for aligning the relative position with the original plate in an exposure apparatus that sequentially exposes the pattern of the original plate to a plurality of regions of the substrate by moving the substrate with respect to the original plate. One or more first alignment marks are provided.

  Further, the substrate holding apparatus of the present embodiment includes an alignment station that measures a position of a second alignment mark arranged for each of a plurality of exposure regions on the substrate with respect to the first alignment mark, and the first alignment mark. Using the alignment mark, the relative position between the substrate holding device and the original plate is aligned, and the position information of the second alignment mark with respect to the first alignment mark obtained by measurement at the alignment station is used as a source. In addition, in an exposure apparatus having an exposure station that moves the substrate and sequentially performs exposure, the substrate holding apparatus is transferred between the alignment station and the exposure station while the substrate is sucked and held. To do.

  Further, the substrate holding apparatus of the present embodiment maintains the pressure by the negative pressure area formed by the suction area and the hollow area when the substrate holding apparatus is transferred between the alignment station and the exposure station. Thus, the substrate is sucked and held without receiving a negative pressure from the outside.

  Further, the substrate holding device of the present embodiment is a scanning exposure apparatus that exposes the original plate and the substrate while scanning the projection optical system in a conjugate manner, and the partition that forms the hollow region is in the scanning direction of the substrate. It is characterized by being arranged in parallel and orthogonal grids, and the interval in the scanning direction between adjacent grids is equal to or smaller than the interval in the direction orthogonal to the scanning direction.

  According to such a configuration, in the exposure apparatus that transfers the substrate holding apparatus between the alignment station and the exposure station, when a so-called vacuum suction type substrate holding apparatus using negative pressure suction is used, the substrate holding apparatus The pressure is maintained by the hollow area provided in the substrate holding apparatus itself and the negative pressure area formed by the adsorption area formed by the substrate and the substrate holding apparatus without dragging the piping that applies the negative pressure during delivery. By doing so, it is possible to continue to hold the substrate without receiving external negative pressure. This makes it possible to transfer the substrate holding device with a simple configuration.

It is a block diagram which shows schematic structure of the exposure apparatus which has the alignment station and exposure station concerning one Embodiment of this invention. It is a top view which shows the state in which the board | substrate holding apparatus hold | maintained the board | substrate which has a shot mark. It is sectional drawing which shows the state in which the board | substrate holding apparatus hold | maintained the board | substrate. It is a figure which shows the board | substrate holding | maintenance apparatus by which the partition is arrange | positioned at the square grid | lattice form. It is a figure which shows the board | substrate holding | maintenance apparatus by which the partition is arrange | positioned at the grid | lattice form of a triangle, a hexagon, and concentric form and radial.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Alignment optical system 2 Substrate 3 Substrate holding device 4 Substrate stage 5 Projection optical system 6 Original plate 7 Chuck alignment optical system 8 Illumination optical system 9 CPU
DESCRIPTION OF SYMBOLS 10 Oblique incident light detection system Focus, tilt detection part 11, 12, 13 Exposure station 21, 22 Alignment station 31 Chuck mark 32 Shot mark 33 Adsorption area 34 Edge bank 35 Hollow area 36 Partition 37 Hole which connects a hollow area and an adsorption area 38 Hole for connecting adjacent hollow regions 39 Valve

Claims (9)

A substrate holding device for adsorbing and holding a substrate by negative pressure,
The main body,
A suction hole for sucking outside air formed in the main body,
A substrate holding apparatus comprising: a first hollow portion formed in the main body portion and communicating with the suction hole. The substrate holding apparatus according to claim 1, further comprising a second hollow portion formed by a wall portion formed so as to surround the suction hole and the substrate on an outer surface of the main body portion. The substrate holding apparatus according to claim 2, wherein a plurality of the second hollow portions are provided, and the plurality of second hollow portions are pressure independent from each other. The substrate holding apparatus according to claim 1, further comprising an on-off valve that opens and closes the first hollow portion. A plurality of the first hollow portions are provided in the main body portion in a state of being partitioned by a partition, and the partition is formed with a hole for selectively communicating the plurality of first hollow portions. The substrate holding apparatus according to claim 1. The substrate holding device is used in an exposure apparatus that exposes a pattern of the original plate on the substrate while relatively scanning the substrate and the original plate, and the partition that forms the first hollow portion is configured to scan the substrate. It is arranged in a lattice shape that is parallel and orthogonal to the direction, and the interval between the adjacent partition walls in the scanning direction is set to be equal to or smaller than the interval in the direction orthogonal to the scanning direction. The substrate holding device according to claim 5. The first hollow portion is disposed at a position where the distance to the surface of the main body portion for sucking and holding the substrate is equal to or larger than the distance to the opposite surface of the main body portion. The substrate holding apparatus according to claim 1. 2. The substrate holding apparatus is used in an exposure apparatus that exposes a pattern of an original on the substrate, and the main body has an alignment mark for positioning a relative position with the original. 8. The substrate holding device according to any one of 7 above. An alignment station that measures relative positions of the plurality of exposure regions on the substrate with respect to the alignment marks, and the substrate based on information on the relative positions of the plurality of exposure regions measured with the alignment station with respect to the alignment marks. An exposure apparatus comprising an exposure station for exposing,
An exposure apparatus, wherein the substrate is transferred between the alignment station and the exposure station in a state where the substrate is sucked and held by the substrate holding apparatus according to claim 8.

Images