JP2007005647A - Mask substrate storage cassette and drawing transfer line for mask substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask substrate storage cassette and a drawing transfer line for a mask substrate that prevent the occurrence of transfer errors of the mask substrate, and allow a user to execute highly reliable mask drawing. <P>SOLUTION: The mask substrate storage cassette has a multistage mounting board 4 on which the end edge of the mask substrate 2 is placed. The mounting board 4 has a downward inclined face 4A and a planar face 4B continuous to the lower end of the inclined face 4A. The mounting boards 4 are provided oppositely to each other so that both end edges of the mask substrate 2 are placed. A length L connecting the intersecting point between the inclined face 4A and the planar face 4B over between both mounting boards is made almost identical with a length Lm between both ends of the mask substrate 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mask substrate storage cassette of a mask drawing apparatus for drawing and forming a circuit pattern on a mask substrate used in an optical exposure apparatus in an LSI manufacturing process, and a drawing conveyance line of the mask substrate.

  A mask substrate storage cassette of a mask drawing apparatus is disclosed in, for example, Japanese Patent Laid-Open No. 9-246367 (Patent Document 1).

  This type of mask substrate storage cassette 1 has a support member 3 on which the mask substrate 2 is placed, as shown in FIGS. The support member 3 has a placement portion 4 on which the edge of the mask substrate 2 is hung. The mounting portion 4 has a downward inclined surface 4D, and the edge of the substrate cassette 2 is hung on the inclined surface 4D.

JP-A-9-246367

  An operator who operates the mask drawing apparatus stores the mask substrate 2 in the mask substrate storage cassette 1 by manual operation or an automatic storage device using a robot or the like. At the time of this storage, as shown in FIG. 9, since both mounting parts 4 are inclined surfaces 4D, the mask substrate 2 may be stored in an inclined state. Due to the storage position error in the mask substrate storage cassette 1 due to the inclination of the mask substrate 2, the following problems have been encountered in the operation of the mask substrate 2 in the transfer process.

  (1). When the mask substrate transfer robot takes out the mask substrate, it comes into contact with or rides on a reference pin for positioning the mask substrate of the positioning mechanism unit, and a transfer error occurs.

  (2). If the mask substrate is largely displaced and placed on the mask substrate positioning mechanism, the pressing mechanism cannot accurately press the end face of the mask substrate, resulting in poor positioning and a transport error.

  (3). When positioning the mask substrate, it is transported to the load lock chamber with a pressing error to the reference pin by the pressing mechanism (a gap between the pin and the mask substrate) and cannot be placed at a predetermined position on the mask substrate transport jig. A transport error occurs.

  In order to cope with the above problems, the object of the present invention is to place the mask substrate in an accurate position without being inclined when the mask substrate is stored in the mask substrate storage cassette. Another object of the present invention is to provide a mask substrate storage cassette and a mask substrate drawing / conveying line in which highly reliable mask drawing is performed without any mask substrate carrying error.

  The present invention is characterized in that, in a mask substrate storage cassette having a multi-stage placement portion on which an edge of the mask substrate is hung, the placement portion has a downwardly inclined surface and a flat surface continuous to the lower end of the inclined surface. To do.

  Further, the present invention provides a load lock chamber that is kept in a vacuum state for waiting a mask substrate to be drawn by a mask drawing apparatus, and a mask substrate position correction before the mask substrate is transferred to the load lock chamber by a transfer robot or the like. In a mask substrate drawing / conveying line having a positioning mechanism unit for performing masking and a mask substrate storage cassette in which a mask substrate transferred by a transport robot or the like is stored in the positioning mechanism unit, the mask substrate storage cassette has an edge of the mask substrate. It has a multi-stage mounting part to be hung, and the mounting part has a downward inclined surface and a flat surface connected to the lower end of the inclined surface.

  According to the present invention, it is possible to provide a mask substrate storage cassette that is placed at an accurate position without tilting the mask substrate. Further, according to the present invention, it is possible to provide a drawing / conveying line for a mask substrate in which mask drawing with high reliability is performed without an error in conveying the mask substrate.

  An embodiment of the present invention will be described with reference to FIGS.

  First, as an example of a mask drawing apparatus, an electron beam drawing apparatus will be described including a drawing conveyance line of a mask substrate.

  The flow from mounting the mask substrate to drawing and forming a circuit pattern on the mask substrate will also be described.

  The mask substrate 2 is stored in the mask substrate storage cassette 1 shown in FIG. 1 by an operator (apparatus operator) using a jig or the like. The mask substrate storage cassette 1 has a support member 3 for holding and storing the mask substrate 2. The support member 3 has a placement portion 4 on which the edge of the mask substrate 2 is hung. By supporting the edge of the mask substrate 2 by placing it on the mounting portion 4, the mask substrate 2 comes into contact with the mounting portion 4, so that the contact area is small and the amount of foreign matter adhering to the mask substrate 2 can be reduced. .

  The mounting portion 4 has a shape similar to an abacus ball. As shown in FIG. 3, the mounting portion 4 has a downwardly inclined surface 4 </ b> A and a flat surface 4 </ b> B connected to the lower end of the inclined surface. The inclination angle θ of the inclined surface is 40 ° to 50 °, and 45 ° is the best. The reason will be described later.

  The mask substrate storage cassette 1 in which the mask substrate 2 is stored is placed on the mask substrate transport unit 5 of the electron beam drawing apparatus shown in FIG. After the drawing file is executed by the operation of the operator, the mask transport unit 5 detects and confirms the presence or absence of the mask substrate 2 in the mask substrate storage cassette 1 by an optical sensor or the like.

  After confirming the location of the mask substrate 2, the mask substrate 2 is taken out of the mask substrate storage cassette 1 by the mask substrate transfer robot 6 and transferred to the mask substrate positioning mechanism 7.

  As shown in FIG. 6, the mask substrate 2 is placed and transported by ΔX and ΔY (about 1 mm) apart from a plurality of mask substrate positioning reference pins 15 arranged in the mask substrate positioning mechanism section 7. Is done.

  After that, the driving unit 17 of the positioning mechanism unit 7 moves the mask pressing plate 16 as a pressing mechanism by Lc, presses the end face of the mask substrate 2 and is pressed against the reference pin 15, thereby positioning the mask substrate 2. Is called.

  This positioning is indispensable for accurately placing the mask substrate 2 at a predetermined position in the mask substrate transfer jig 9 placed in the load lock chamber 8.

  After positioning, the mask substrate 2 is transferred to the load lock chamber 8 opened to the atmosphere by another transfer robot (not shown), and placed on the mask substrate transfer jig 9 in the load lock chamber 8. .

  A conveyance path from the mask substrate storage cassette 1 to the load lock chamber 8 is a drawing conveyance line for the mask substrate.

  After the transfer of the mask substrate is completed, the load lock chamber 8 is shut off from the atmosphere and evacuated. Thereafter, the mask substrate 2 is transferred to the drawing chamber 10 together with the mask substrate transfer jig 9, mounted on the XY stage 11, and electrostatically attracted and fixed by the electrostatic chuck 12.

  The mask substrate 2 is positioned by the XY stage 11, and a circuit pattern is drawn and formed on the mask substrate 2 by the electron beam 14 that is shaped and controlled based on the circuit pattern data in the column 13 in which the electron optical system is incorporated. Is done.

  After drawing, the mask substrate 2 is taken out together with the mask substrate transfer jig 9 from the XY stage 11 and carried out from the drawing chamber 10 to the load lock chamber 8. After the load lock chamber 8 is opened to the atmosphere, the mask substrate 2 is removed from the mask substrate transfer jig 9 and is carried out and stored in the mask substrate storage cassette 1 by the mask substrate transfer robot 6. The operator takes out the mask substrate 2 on which drawing has been completed from the mask substrate storage cassette 1, and thereafter, necessary process processing is performed.

  As described above with reference to FIG. 3, the mounting portion 4 of the mask substrate storage cassette 1 has the downward inclined surface 4 </ b> A and the flat surface 4 </ b> B continuous to the lower end of the inclined surface. Therefore, even if the mask substrate 2 is placed obliquely so that the edge of the mask substrate 2 is in contact with one inclined surface 4A, the mask substrate 2 slides on the inclined surface 4A and the edges on both sides of the mask substrate 2 are flat. It is mounted so as to be hung on the surface 4B. The mask substrate 2 is placed in a stable state on the flat surface 4B without being inclined.

  Accordingly, the mask substrate 2 is accurately placed at a predetermined position without being displaced on the placement portion 4 of the mask substrate storage cassette 1. Therefore, when the transfer robot 6 transfers the mask substrate 2 in the mask substrate storage cassette 1 to the positioning mechanism unit 7, ΔX and ΔY (about 1 mm) with respect to a plurality of mask substrate positioning reference pins 15. It can be placed securely at a distance.

  There is no mounting failure on the positioning mechanism, which causes the mask substrate to contact or ride on a reference pin for positioning the mask substrate of the positioning mechanism as in the prior art, and no mask substrate transport error occurs. For this reason, it is possible to provide a drawing transport line for the mask substrate on which highly reliable mask drawing is performed.

  The support member 3, particularly the inclined surface 4 </ b> A and the flat surface 4 </ b> B, use members that are slippery and have low frictional resistance. Further, the inclined surface 4A and the flat surface 4B are processed so as to reduce the surface roughness. Thereby, the sliding of the inclined surface 4A becomes better.

  The inclined surface 4A is best at 45 °. When the angle is reduced, the slope of the inclined surface 4A becomes loose, and the mask substrate 2 becomes less slippery. Since there is a possibility that the mask substrate 2 may be inclined such that both end edges of the mask substrate 2 do not touch the flat surface 4B, the inclination of the inclined surface 4A is preferably 40 ° or more.

  On the contrary, when the angle is increased, the slope of the inclined surface 4A becomes steep and the slippage is improved. However, the sliding speed increases, the collision with the carrier surface 4B increases, and the problem of dust generation occurs. Further, since the opening width between both support members 3 is narrow, it is difficult to put in and out the mask substrate. Therefore, the inclination of the inclined surface 4A is desirably 50 ° or less.

  As shown in FIG. 2, the mounting portions 4 of the support member 3 are provided facing each other so that both end edges of the mask substrate 2 are hung. The length L connecting the intersection of the inclined surface 4A and the flat surface 4B across the mounting portions 4 and the length Lm between both ends of the mask substrate 2 are substantially the same.

  As a result, the mask substrate 2 is placed on the mask substrate storage cassette 1 so that the corners of both end edges of the mask substrate 2 are in contact with the intersection of the inclined surface 4A and the flat surface 4B. , Will be placed more accurately.

  The placement accuracy of the mask substrate 2 placed on the mask substrate storage cassette 1 is improved, and the mask substrate 2 transferred to the positioning mechanism unit 7 is placed with almost no displacement. For this reason, there is no conveyance error, and mask drawing with high reliability can be realized.

  In addition, the mounting portion 4 has a shape having an inclined surface 4A and a flat surface 4B. If it is difficult to make the same dimensions when processing, there is a problem even if there is a difference in length of about 0.5 to 1 mm. No.

  Further, as shown in FIG. 4, it is desirable that the mounting portion 4 slightly inclines the flat surface 4B when it is desired to minimize the contact area with the mask substrate. The inclination angle θp of the flat surface 4B is about 5 ° or less. It is desirable that the inclination angle θ of the inclined surface 4A for sliding the mask substrate 2 is made extremely smaller and that the intersection with the inclined surface 4A does not become an acute angle.

  The positioning of the positioning mechanism will be described in detail with reference to the drawing conveyance line of the mask substrate. Reference is made to FIG.

  The mask substrate is transported on a mask substrate drawing transport line from the mask substrate storage cassette 1 to the load lock chamber 8.

  The mask substrate storage cassette 1 stores mask substrates 2 in multiple stages. The mask substrate transfer robot 6A removes the mask substrate 2 from the mask substrate storage cassette 1 and places it on the positioning mechanism portion 7A or the positioning mechanism portion 7B.

  Although two types of positioning mechanism portions 7A and 7B have been described, there is usually only one positioning mechanism portion provided on the drawing / conveying line of the mask substrate.

  The positioning mechanism portions 7A and 7B have holding pins 30. The mask substrate 2 is placed on the holding pins 30. In the positioning mechanism portion 7A, the mask pressing plate 16 (pressing mechanism) is pressed so as to press the mask substrate 2 against the reference pin 15. Thereby, the positioning of the mask substrate 2 is performed.

  In the positioning mechanism portion 7B, the mask substrate 2 is sandwiched between a pair of mask pressing plates 16 (pressing mechanism). That is, the mask substrate 2 is pressed by the pressing mechanism so as to be pressed from the diagonal direction, and the mask substrate 2 is positioned.

  The mask substrate 2 that has been positioned is transferred to the load lock chamber 8 by the mask substrate transfer robot 6B and placed on the mask substrate transfer jig 9.

  If the mask substrate 2 is transported in such a manner and the positioning accuracy of the mask substrate 2 placed in the mask substrate storage cassette 1 is not well positioned, the positioning mechanisms 7A and 7B cannot be positioned, resulting in a transport error.

  That is, when the transfer robot 6A transfers the mask substrate 2 to the positioning mechanisms 7A and 7B, the mask substrate 2 is placed on the holding pins 30. Usually, the contact of the holding pins 30 to the back surface of the mask substrate 2 is limited to a limited region having an outer periphery of about 5 mm or less. For this reason, the holding pin 30 is placed within a range of about 1.5 to 3 mm from the outer periphery of the mask substrate in consideration of the amount of movement during the positioning operation. If the position of the mask is shifted by about 1.5 mm when it is transported by the transport robot 6A, it may not be correctly placed on the holding pin 30 and may cause a drop transport accident (transport error).

  Further, the mask substrate is placed with a certain distance offset from the reference pin 15 so that the transferred mask substrate is not placed on the reference pin 15 of the positioning mechanism portion 7A. In order to prevent the mask substrate from falling off the holding pins 30 even under such mounting conditions, the offset amount with respect to the reference pins 15 is about 0.5 to 1 mm.

  Therefore, when the position difference of the mask substrate in the mask substrate storage cassette 1 is 0.5 mm or more, there is a possibility that it may lead to a transportation accident such as riding on the reference pin 15 or dropping of the mask substrate from the holding pin 30.

  Causes of positional deviation of the mask substrate include vibrations when the operator carries the mask substrate storage cassette, impacts when the mask substrate storage cassette is set in the transport unit 5, and every time the mask substrate is stored by a hand or a robot. However, it is difficult to make them all zero.

  In order not to cause these transport troubles, the mask substrate needs to be within a certain amount of deviation before the mask substrate is transported to the positioning mechanism.

  Therefore, the most effective means for suppressing the shift amount before positioning by the positioning mechanism is to narrow the degree of play of the cassette substrate in the mask substrate storage cassette. By making the opening / closing opening size of the mask substrate storage cassette formed by the support member 3 as close as possible to the outer shape of the mask substrate, the backlash of the mask substrate in the mask substrate storage cassette can be suppressed, and as a result, the shift amount can be suppressed. Connected.

  However, it becomes difficult to put the mask substrate in and out of the mask substrate storage cassette by the transfer robot, which is not practical.

  In the embodiment of the present invention, as described above, the mounting portion 4 of the support member 3 is provided with the downward inclined surface 4A and the flat surface 4B connected to the lower end of the inclined surface. Thereby, the degree of play of the cassette substrate 2 in the mask substrate storage cassette 1 can be narrowed, and the positional deviation of the cassette substrate 2 can be suppressed. In addition, since the size of the opening / closing opening of the mask substrate storage cassette cannot be reduced, the mask substrate can be easily put in and out of the mask substrate storage cassette by the transfer robot without any trouble.

It is a figure which concerns on the Example of this invention, and is a figure which shows the external appearance of a mask substrate storage cassette. It is a figure which concerns on the Example of this invention, and is a figure which shows the positional relationship of a mask substrate and a mounting part. FIG. 5 is a diagram illustrating a positional relationship between a mask substrate and a mounting portion when the mask substrate is placed on the mask substrate storage cassette according to the embodiment of the present invention. It is a figure concerning the Example of this invention, and is a figure which shows the other Example of a mounting part. 1 is a diagram illustrating an outline of an electron beam drawing apparatus according to an embodiment of the present invention. It is a figure which concerns on the Example of this invention and is a figure which shows the structure of a positioning mechanism part. It is a figure which concerns on the Example of this invention, and is a figure which shows the drawing conveyance line of a positioning mechanism part and a mask board | substrate. It is a figure which concerns on a prior art example, and is a figure which shows the external appearance of a mask substrate storage cassette. FIG. 10 is a diagram showing a positional relationship between a mask substrate and a placement portion when a mask substrate is placed on a mask substrate storage cassette according to a conventional technique.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Mask substrate storage cassette, 2 ... Mask substrate, 3 ... Mask substrate support member, 4 ... Mask substrate mounting part, 4A ... Inclined surface, 4B ... Flat surface, 5 ... Mask substrate conveyance unit, 6, 6A, 6B ... Mask substrate transfer robot, 7 ... Positioning mechanism, 8 ... Load lock chamber, 9 ... Mask substrate transfer jig, 10 ... Drawing chamber, 11 ... XY stage, 12 ... Electrostatic chuck, 13 ... Column, 14 ... Electron beam, 15 ... reference pin, 16 ... pressing plate for mask substrate, 17 ... driving unit.

Claims (9)

In the mask substrate storage cassette having a multi-stage placement section on which the edge of the mask substrate is hung
The mask substrate storage cassette according to claim 1, wherein the placement unit has a downward inclined surface and a flat surface continuous with a lower end of the inclined surface. The mask substrate storage cassette according to claim 1,
The mask substrate storage cassette, wherein the flat surface is inclined downward at an inclination angle smaller than that of the inclined surface. The mask substrate storage cassette according to claim 1,
The mounting portion is provided facing each other so that both end edges of the mask substrate are hung,
A mask substrate storage cassette characterized in that a length L connecting an intersection of the inclined surface and the flat surface across the mounting portions is substantially the same as a length Lm between both ends of the mask substrate. In the mask substrate storage cassette according to any one of claims 1 to 3,
2. The mask substrate storage cassette according to claim 1, wherein an inclination angle of the inclined surface is in the vicinity including 45 °. In the mask substrate storage cassette according to claim 2,
A mask substrate storage cassette, wherein the flat surface has an inclination angle of 5 ° or less. A load lock chamber in which a mask substrate to be drawn by a mask drawing apparatus is kept in a vacuum state, and a positioning mechanism for correcting the position of the mask substrate before transferring the mask substrate to the load lock chamber by a transfer robot or the like A mask substrate drawing transport line including a mask substrate storing cassette storing the mask substrate transported to the positioning mechanism unit by a transport robot or the like,
The mask substrate storage cassette has a multi-stage mounting portion on which an edge of the mask substrate is hung,
The mask substrate drawing / conveying line characterized in that the placement portion has a downward inclined surface and a flat surface connected to the lower end of the inclined surface. In the drawing conveyance line of the mask substrate according to claim 6,
The mask substrate drawing / conveying line, wherein the positioning mechanism section includes a reference pin that determines a position of the mask substrate, and a pressing mechanism that presses the mask substrate against the reference pin. In the drawing conveyance line of the mask substrate according to claim 6,
The positioning mechanism section has a pair of pressing mechanisms for pressing the mask substrate from a diagonal direction. In the drawing conveyance line of the mask substrate according to claim 6,
The drawing transport line for a mask substrate, wherein the positioning mechanism portion has a holding pin for holding the mask substrate.

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