JP2010161189A - Substrate positioning apparatus and substrate positioning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate positioning apparatus improved in accuracy and the yield of a reticle by correcting a reticle precursor position by measuring slippage of a pattern center with respect to a reticle center in a mask drawing apparatus, and to provide a substrate positioning method. <P>SOLUTION: The substrate positioning device includes: a plurality of positioning means (positioning pins) each having an actuator built-in for positioning the substrate by pressing the substrate against them; and a control unit positioning the substrate by controlling the actuators. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a substrate positioning apparatus and a substrate positioning method, and more particularly to a reticle substrate positioning apparatus and a substrate positioning method used in a semiconductor lithography process.

  In general, a pattern requiring fine processing such as a semiconductor device manufacturing process is formed by using an original plate called a reticle and transferring the pattern onto a wafer by a reduction projection exposure apparatus (hereinafter referred to as an exposure apparatus) called a scanner or a stepper. The so-called photolithography method is used. Here, the reticle refers to a photomask used to expose a highly integrated electric circuit pattern on a wafer in a semiconductor device manufacturing process. A reticle is usually provided with a plurality of alignment marks for positioning when loaded on a reticle fixing stage of an exposure apparatus and for overlaying when a pattern formed on a wafer is exposed. Used.

  In general, the center position of the pattern formed on the reticle is shifted from the center of the reticle. In order to adjust this misalignment, alignment is performed between the reference mark provided on the reticle fixing stage and the alignment mark on the reticle. In other words, a reticle or a mechanism for moving the reticle stage is provided so that the reference mark and the alignment mark are aligned on the reticle stage.

  Although the reticle has the above-described mechanism, the center position of the pattern needs to be within a certain accuracy with respect to the reticle center. This is because the protrusion sticks out from the vacuum suction portion that fixes the reticle on the reticle stage.

  In addition, for a super-resolution mask that is a reticle having a multi-stage structure, the first-layer reticle pattern including the alignment mark is etched, and then the second-layer drawing is performed. At this time, the drawing apparatus detects the alignment mark information formed in the first layer and draws the pattern of the second layer so as to overlap the first layer, but the pattern center of the first layer is shifted from the reticle center. As a result, there may be a problem when drawing the second layer.

  Unlike the reticle stage of the exposure apparatus, the stage of the mask drawing apparatus normally does not have a rotation mechanism. When the reticle is rotated in the drawing stage during pattern drawing of the second layer, the stage It is necessary to match both the movement direction of the pattern and the pattern drawing direction with the rotation shift direction.

  Due to the high degree of pattern integration, the current semiconductor reticles are mainly patterned by a variable shaping type drawing apparatus using an electron beam having a higher resolution than a laser as an exposure source. This is to create a beam of an arbitrary size such as a rectangle or a triangle through two slits from an electron beam irradiated from an electron gun.

  Specifically, the electron beam irradiated from the electron gun passes through the first shaping slit, is adjusted to a certain size, and then projected onto the second shaping slit. By controlling the beam position projected onto the second shaping slit by the shaping deflector at the time of projection, the shape and size of the beam are changed.

  In this way, when the beam itself is shaped, it is necessary to rotate not only the beam scanning direction but also the shaped beam itself when performing drawing in accordance with the rotation of the reticle master, and there is no rotation stage. In addition, there are cases where it is very difficult to perform overdrawing using a variable shaping type electron beam drawing apparatus. For this reason, in the variable shaping type drawing apparatus, a limit value is provided for the amount of rotational deviation of the reticle calculated from the alignment mark as the guaranteed accuracy at the time of overlapping drawing.

  As described above, the tolerance of positional deviation with respect to the reticle center of the reticle pattern is very small, and it is important that the reticle original is loaded at the correct position in the mask drawing apparatus.

  Hereinafter, the reticle master fixing procedure will be described. 2 to 5 are schematic sectional views showing a substrate positioning procedure of a conventional substrate positioning apparatus. Specifically, the stage part of the electron beam mask drawing apparatus is shown. As shown in FIG. 2, the structure which conveys the board | substrate 21, prescribes | regulates a position, and fixes to the stage 22 is shown. The substrate 21 is carried to a stage part in a vacuum via a load lock chamber (not shown). After that, as shown in FIG. 3, the substrate 21 is placed on the substrate lower surface support portion 24 by the transporter 23. Next, as shown in FIG. 4, the Y-direction pressing pin 25 presses the substrate 21 until it hits the Y-direction positioning pin 26, and in this state, the X-direction pressing pin 27 hits the substrate 21 against the X-direction positioning pin 28. Press until. As shown in FIG. 5, the substrate 21 thus positioned is fixed to the stage so as to be sandwiched between the substrate upper surface support portions 29 installed at positions facing the substrate lower surface support portions 24. The reason why the substrate 21 is fixed from above and below is to prevent the substrate 21 from being distorted by mechanical stress at the time of fixing and affecting the position accuracy of the pattern.

  As described above, the reticle original plate is positioned on the basis of the outer shape in the drawing apparatus, and is fixed to the drawing stage by several fixing portions opposed in the vertical direction. If the reticle original plate does not correctly hit the fixed pin side at the time of pressing shown in FIG. 4, drawing is performed while the reticle is displaced from the drawing stage. Further, if the fixing of the substrate 21 shown in FIG. 5 is incomplete, the reticle master may be displaced from the fixing portion while the drawing proceeds and the stage moves.

  In order to correct the misalignment of the reticle original plate, for example, it is conceivable to employ a precision reticle transport robot that can finely adjust the reticle in the translational and rotational directions. However, this means that another precision control device other than the drawing stage is installed in the chamber of the drawing device, and calibration and maintenance of the unit itself are required. As a result, the load on the mask apparatus is greatly increased.

JP 2006-351750 A

  The present invention relates to a substrate positioning apparatus and a substrate positioning method capable of measuring a deviation of a pattern center with respect to a reticle center in a mask drawing apparatus, correcting the reticle original position, and improving the accuracy and yield of the reticle. Is to provide.

  The invention according to claim 1 of the present invention includes a plurality of positioning means each of which includes an actuator and presses the substrate to position the substrate, and a control unit that controls the actuator to position the substrate. A substrate positioning apparatus characterized by the above.

  The invention according to claim 2 of the present invention is arranged on a stage and supports a substrate, a plurality of positioning means for positioning the substrate, each having a built-in actuator, and transporting the substrate into the stage, Substrate transport means for placing the substrate on the substrate support so that the substrate contacts the plurality of positioning means, a plurality of substrate position detection means for measuring the position of the end face of the substrate, and outputs of the plurality of substrate position detection means And a control unit for positioning the substrate by controlling the actuator according to the above.

  The substrate according to claim 3 of the present invention is characterized in that the substrate position detecting means measures the distance from the end face of the substrate or the position of the alignment mark formed on the substrate. This is a positioning device.

  In the invention according to claim 4 of the present invention, the substrate is conveyed into the stage, the substrate is brought into contact with a plurality of positioning means, the position of the side surface of the substrate is measured by an interferometer, and the plurality of positioning is performed based on the measurement result. The substrate positioning method is characterized in that the position of the substrate is corrected by controlling an actuator built in the contact portion of the means of the substrate.

  The invention according to claim 5 of the present invention is characterized in that the measurement is measurement of a distance from an end face of the substrate or measurement of a position of an alignment mark formed on the substrate. This is a positioning method.

  According to the present invention, a substrate positioning apparatus and a substrate capable of measuring the deviation of the pattern center with respect to the center of the reticle in the mask drawing apparatus, correcting the reticle original plate position, and improving the accuracy and yield of the reticle. A positioning method can be provided.

It is a schematic sectional drawing which shows the board | substrate positioning device which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the procedure of the board | substrate positioning of the conventional board | substrate positioning apparatus. It is a schematic sectional drawing which shows the procedure of the board | substrate positioning of the conventional board | substrate positioning apparatus. It is a schematic sectional drawing which shows the procedure of the board | substrate positioning of the conventional board | substrate positioning apparatus. It is a schematic sectional drawing which shows the procedure of the board | substrate positioning of the conventional board | substrate positioning apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiments, the same components are denoted by the same reference numerals, and redundant description among the embodiments is omitted.

  FIG. 1 is a schematic sectional view showing a substrate positioning apparatus according to an embodiment of the present invention. Here, the substrate positioning apparatus according to the embodiment of the present invention refers to an apparatus that determines the position of the reticle in the mask drawing apparatus. As shown in FIG. 1, a substrate positioning apparatus according to an embodiment of the present invention includes a substrate support unit that supports a substrate and positioning means (positioning pins) for positioning the substrate, each of which incorporates an actuator. 10) Substrate transport means for transporting the substrate into the stage and placing the substrate on the substrate support so that the substrate is brought into contact with the plurality of positioning means, and multiple substrate position detections for measuring the position of the end face of the substrate A means (interferometer) 11 and a control unit 12 for positioning the substrate by controlling the actuator according to the outputs of the plurality of substrate position detecting means are provided.

  As shown in FIG. 1, the substrate positioning device according to the embodiment of the present invention has an actuator 10 built in the substrate contact portion of the positioning pin, unlike the conventional substrate positioning device shown in FIG. 2. There are various types of actuators 10 such as hydraulic pressure, pneumatic pressure, electromagnetic type, etc. Among them, the piezoelectric type is small and has a fast response speed, and can perform precise expansion and contraction operation in submicron units. For example, in the case of a 6-inch square substrate, in order to rotate by 0.1 mrad, the substrate may be moved in the direction of rotation of about 8 μm. In the embodiment of the present invention, the piezoelectric actuator 10 has a sufficient position control resolution in consideration of the alignment accuracy of the butting method. Since there are two fixing pins in the substrate Y direction, the reticle master can be rotated by individually controlling these two actuators 10.

  In the embodiment of the present invention, an interferometer 11 that measures the position of the reticle end surface is provided. Although there are various types of interferometers 11, since the reticle as the target material is made of glass having optical transparency, it is desirable to use the oblique incidence type interferometer 11 in order to increase the reflectance. As for the measurement accuracy, similarly to the actuator 10 described above, in the embodiment of the present invention, it is sufficient if detection can be made with an accuracy of the order of several μm.

  The substrate positioning apparatus according to the embodiment of the present invention controls the actuator 10 by the control unit 12 based on the information of the interferometer 11, and at the same time, the stage position coordinates corresponding to the center position of the reticle, which is a parameter of the mask drawing apparatus. By correcting the above, it is possible to correct the rotation and translational deviation when the reticle original plate is set.

  In addition, even if the reticle original plate is shifted after drawing is started, it can be detected by the interferometer 11 during drawing or after drawing is finished. Further, if the rotation of the reticle original is confirmed from the first layer alignment mark information at the time of overlay drawing, the reticle rotation correction based on the amount of the rotational deviation can be easily performed, and the overlay drawing accuracy is improved. be able to.

  Next, a substrate positioning method according to the embodiment of the present invention will be described. First, the substrate is transferred into the stage, and the substrate is brought into contact with a plurality of positioning means. Next, the position of the side surface of the substrate is measured by the interferometer 11. The interferometer 11 is used to measure the distance from the end face of the substrate or the position of the alignment mark formed on the substrate. Based on the measurement results, the position of the substrate is corrected by controlling the actuator 10 built in the substrate contact portion of the plurality of positioning means.

  Next, examples of the present invention will be described. In the embodiment of the present invention, a square substrate precision positioning stage was used.

  As shown in FIG. 1, in a positioning pin (material: PEEK) that comes into contact with the square substrate, a laminated piezoelectric actuator 10 that matches the curved surface of the pin is embedded in three positioning pins, and the positioning pin comes into contact with the square substrate. The specification is such that a stretchable surface of 10 mm in length and 2 mm in width is exposed. Further, an oblique incidence laser interferometer 11 that measures the positions of the side surfaces of one end surface in the substrate X direction and two end surfaces in the substrate Y direction was installed at a position approximately 2 cm away from the substrate end surface. A 6-inch reticle reticle was loaded into the substrate positioning device, and alignment was performed with a pressing pin made of the same material as the positioning pin.

  When the end face of the substrate after position fixing was measured with the interferometer 11, a distance difference of 0.23 mm was detected between the two interferometers 11 on the end face in the substrate Y direction. For this reason, once the reticle original plate was removed, the laminated piezoelectric actuator 10 was adjusted and the alignment was performed again, the distance difference value could be driven to a value within 0.02 mm (with a rotation angle within 0.1 mrad). .

  In the embodiment of the present invention, the misalignment of the pattern center with respect to the reticle center is measured using the oblique incidence laser interferometer 11 that measures the position of the side surface of one end surface in the substrate X direction and two end surfaces in the substrate Y direction. The deviation of the reticle original plate position can be corrected by adjusting the laminated piezoelectric actuator 10 and performing the alignment again, and the accuracy and yield of the reticle can be improved.

  DESCRIPTION OF SYMBOLS 10 ... Actuator, 11 ... Interferometer, 12 ... Control unit, 21 ... Board | substrate, 22 ... Stage, 23 ... Conveyor, 24 ... Substrate lower surface support part, 25 ... Y direction pressing pin, 26 ... Y direction positioning pin, 27 ... X direction pressing pin, 28 ... X direction positioning pin, 29 ... Substrate upper surface support part

Claims (5)

A plurality of positioning means each for positioning the substrate by pressing the substrate with a built-in actuator;
A control unit for controlling the actuator to position the substrate;
A substrate positioning apparatus comprising: A substrate support unit disposed on the stage and supporting the substrate;
A plurality of positioning means each of which incorporates an actuator and positions the substrate;
Substrate transport means for transporting the substrate into the stage and placing the substrate on the substrate support so as to contact the substrate with the plurality of positioning means;
A plurality of substrate position detecting means for measuring the position of the end face of the substrate;
A control unit for positioning the substrate by controlling the actuator in accordance with outputs of the plurality of substrate position detecting means;
A substrate positioning apparatus comprising:   The substrate positioning apparatus according to claim 2, wherein the substrate position detecting unit measures a distance from an end face of the substrate or a position of an alignment mark formed on the substrate. Transport the substrate into the stage, contact the substrate with a plurality of positioning means,
Measure the position of the side of the substrate with an interferometer,
A substrate positioning method, wherein the position of the substrate is corrected by controlling an actuator built in the contact portion of the substrate of the plurality of positioning means based on the measurement result.   5. The substrate positioning method according to claim 4, wherein the measurement is a measurement of a distance from an end surface of the substrate or a position of an alignment mark formed on the substrate.

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