JP2010204545A - Mask for exposure evaluation and exposure evaluation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask for exposure evaluation and an exposure evaluation method for securing to what degree items resulting from a device among causes of generation of exposure unevenness affect with sufficient accuracy in an exposure device which performs exposure using the mask. <P>SOLUTION: The mask Ma for exposure evaluation includes: first areas a1, a3, a5, ..., having patterns based on a design value; and second areas a2, a4, ..., having patterns for giving deviation of exposure amounts to the design value adjacent to the first areas. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mask for exposure evaluation and an exposure evaluation method, and more particularly, for exposure evaluation for improving performance when manufacturing a pattern on a substrate of a large flat panel display such as a liquid crystal display or a plasma display. The present invention relates to a mask and an exposure evaluation method.

  In recent years, a photolithography method has been adopted as a method for manufacturing a color filter of a large flat panel display such as a liquid crystal display or a plasma display. Usually, in the photolithography method, a resist is applied to a cleaned glass substrate, pre-baked, then exposed using a mask, and then developed, washed, baked, and the like to form a pattern.

  As an exposure method, for example, there is a method in which a mask pattern is transferred onto a substrate by proximity exposure transfer using a divided sequential exposure method. As this type of divided sequential exposure method, for example, a mask having the same size as the panel is used, the mask is held by a mask stage, the substrate is held by a work stage, and both are placed close to each other. Each time the work stage is moved stepwise relative to the mask, the substrate is irradiated with light for pattern exposure from the mask side, and a plurality of mask patterns are exposed and transferred onto the substrate.

  As another exposure method, a proximity scan exposure method is known in which a mask is subdivided, a plurality of mask holding portions for holding these masks are arranged in a staggered manner, and exposure is performed while moving the substrate in one direction. Yes. This exposure method utilizes the fact that a large pattern can be formed by joining together on the premise that there is a portion that is repeated to some extent in the pattern formed on the substrate. In this case, the mask does not need to be large in accordance with the panel, and a relatively inexpensive mask can be used.

  By the way, when exposure is performed using a multi-head exposure apparatus having a plurality of mask holding units and irradiation units, there is a concern about uneven exposure between the heads. The cause of uneven exposure is due to the difference in exposure amount, misalignment, and gap due to the apparatus. In addition, resist and developer materials, resist film thickness, resist drying temperature and drying time, development time Due to process conditions such as. Since the degree of unevenness of exposure is generally based on human visual confirmation, it has been difficult to clarify the degree of improvement even if the numerical values of the apparatus-derived items are changed.

  As a method for evaluating exposure unevenness, an evaluation element (TEG) that evaluates line width and resistance in an overlapped exposure region is used to compare a measured value in a head drawing boundary with a measured value in a single exposure region. In some cases, the positional adjustment deviation of the head is detected (see, for example, Patent Document 1).

JP 2008-276168 A

  Incidentally, the evaluation method described in Patent Document 1 is a technique limited to evaluation of position and resistance in direct drawing exposure, and does not cover elements of exposure unevenness when exposure is performed using a mask.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to what extent the items attributable to the apparatus are affected among the causes of exposure unevenness in an exposure apparatus that uses a mask for exposure. It is an object of the present invention to provide an exposure evaluation mask and an exposure evaluation method that can accurately grasp the above.

The above object of the present invention can be achieved by the following constitution.
(1) a first region having a pattern based on a design value;
A second region having a pattern adjacent to the first region to give at least one shift of an exposure amount, a position, and a gap amount with respect to the design value;
A mask for exposure evaluation, comprising:
(2) A plurality of the first regions and the second regions are provided so as to be alternately arranged,
The exposure evaluation mask according to (1), wherein in the plurality of second regions, at least one shift amount of an exposure amount, a position, and a gap amount is different from the design value.
(3) A plurality of the first regions and the second regions are provided so as to be alternately arranged,
The mask for exposure evaluation according to (1) or (2), wherein a plurality of boundary portions between the first region and the second region are inclined at different angles.
(4) The exposure evaluation mask according to any one of (1) to (3), wherein the pattern of the first and second regions is a linear pattern or a continuous pattern.
(5) a substrate transport mechanism capable of transporting the substrate reciprocally along a predetermined direction, a plurality of mask holding portions capable of respectively holding a plurality of masks in a state of being separated from the transported substrate, and the plurality of masks An exposure evaluation method using a proximity scan exposure apparatus, each of which is disposed above a mask holding unit and includes a plurality of irradiation units that irradiate exposure light,
A step of holding the mask for exposure evaluation according to any one of (1) to (4) in any one of the plurality of mask holding portions;
Irradiating the exposure light to the transported substrate through the exposure evaluation mask, and exposing the pattern of the exposure evaluation mask to the substrate;
Evaluating the pattern transferred and exposed to the substrate;
An exposure evaluation method comprising:

  According to the mask for exposure evaluation of the present invention, the first region having a pattern based on the design value and at least one shift of the exposure amount, the position, and the gap amount with respect to the design value adjacent to the first region. And a second region having a pattern for providing at least one of an exposure amount difference, a positional deviation difference, and a gap difference caused by the exposure apparatus by evaluating the exposed substrate using an evaluation mask. It is possible to accurately grasp how much the unevenness is affected.

(A) is the fragmentary top view of the mask for exposure evaluation for evaluating the exposure nonuniformity by the shift | offset | difference of the exposure amount concerning 1st Embodiment of this invention, (b) is the I section enlarged view of (a). (C) is an enlarged view of a portion I ′ of (a). (A) is the fragmentary top view of the mask for exposure evaluation for evaluating the exposure nonuniformity by the position shift which concerns on 1st Embodiment of this invention, (b) is the II section enlarged view of (a). (C) is the II 'section enlarged view of (a), (d) is the II "section enlarged view of (a). (A) is the fragmentary top view of the mask for exposure evaluation for evaluating the exposure nonuniformity by the gap | deviation of gap amount which concerns on 1st Embodiment of this invention, (b) is the III section enlarged view of (a). It is. (A) is a graph showing a light intensity distribution when exposed with a gap amount of 150 μm and 200 μm according to a design value pattern, and (b) is a graph of light when exposed with a gap amount of 200 μm according to a design value pattern. It is a graph which shows intensity distribution and intensity distribution of light at the time of exposing with the gap amount of 150 micrometers by the pattern which has a main opening part and an auxiliary opening part. It is a top view of the proximity scan exposure apparatus which is an example used for the exposure evaluation method of this invention. FIG. 6 is a side view of the scan exposure apparatus in FIG. 5. It is the fragmentary top view of the mask for exposure evaluation for evaluating the exposure nonuniformity by the gradation which concerns on 2nd Embodiment of this invention, (b) is the VII part enlarged view of (a), (c) is It is the VII 'part enlarged view of (a).

  Embodiments of an exposure evaluation mask and an exposure evaluation method according to the present invention will be described below in detail with reference to the drawings.

(First embodiment)
In the present embodiment, using the three types of exposure evaluation masks Ma to Mc shown in FIGS. 1 to 3, in the multi-head exposure apparatus, among the causes of exposure unevenness (streaks unevenness), it is attributed to the apparatus. Each of the exposure amount difference, misregistration difference, and gap difference is evaluated.

  In the exposure evaluation mask Ma shown in FIG. 1, a plurality of patterns (rectangular windows) are formed in a straight line, and a plurality of first regions a1, a3, a5 having a pattern p based on a design value. ,... And a plurality of second areas a 2, a 4,... Having a pattern pa that shifts the exposure amount with respect to the design value are alternately arranged. The exposure amounts of a4,... are made different so that the deviation becomes larger in stages.

  Specifically, in the mask Ma, as shown in FIGS. 1B and 1C, the line width w of the pattern p in the first regions a1, a3, a5 is set to 100 μm, and the pattern pa in the second region a2. The line width w1 is 102 μm, the line width w2 of the pattern pa in the second region a4 is 104 μm, and the difference in line width is given as a deviation in exposure amount. Further, there is no positional shift at the boundary between the first regions a1, a3, a5 and the second regions a2, a4, and the inter-pattern distance d between the regions a1, a2, a3, a4, a5,. Is 0.3 mm. In the second regions a2, a4,..., The line widths may be reduced so that the exposure amount deviation is gradually reduced.

  In the exposure evaluation mask Mb shown in FIG. 2, a plurality of patterns (rectangular windows) are formed in a straight line, and a plurality of first regions b1, b3, b5 having a pattern p based on the design value. , And a plurality of second regions a2, a4,... Having a pattern pb that is displaced from the design value, are arranged alternately, and the second regions a2, a4, The amount of misalignment is different so as to spread in stages.

  Specifically, in the mask Mb, as shown in FIGS. 2B to 2D, the line width w of the patterns p and pb of each region b1, b2, b3, b4, b5,. The distance d is set to 0.3 mm. On the other hand, the position of the second region b2 is shifted by the shift amount β1 (= 2 μm) with respect to the positions of the first regions b1 and b3, and the distance between the first region b1 and the second region b2 is set to 0. 302 mm, and the distance between the second region b2 and the third region b3 is 0.298 mm. Further, the position of the second region b4 is shifted by the shift amount β2 (= 4 μm) with respect to the positions of the first regions b3, b5, and the interval between the first region b3 and the second region b4 is set to 0. The distance between the second region b4 and the third region b5 is set to be 0.296 mm.

  In the exposure evaluation mask Mc shown in FIG. 3, a plurality of patterns (rectangular windows) are formed in a straight line, and a plurality of first regions c1, c3, c5 having patterns p based on design values. ,... And a plurality of second regions c2, c4,... Having a pattern pc that shifts the gap amount with respect to the design value are alternately arranged, and the second regions c2, c4 are arranged. ,... Are different from each other so as to increase in steps.

  Specifically, in the mask Mc, as shown in FIG. 3B, the inter-pattern distance d of each of the regions c1, c2, c3, c4, c5,. The line width w of the pattern p of c3, c5,. On the other hand, the pattern pc of the second region c2 has a line width w of 100 μm so as to shift the gap amount of the second region c2 with respect to the first regions c1, c3, c5,. It is constituted by a main opening and sub-openings provided on both sides of the main opening that are not resolved after development processing.

  Thereby, when the gap between the mask Mc and the substrate W is exposed at 150 μm, the light intensity distribution as shown in FIG. 4A is obtained in the pattern p of the first regions c1, c3, and c5. On the other hand, in the pattern pc of the second region c2, a light intensity distribution as shown in FIG. 4B is obtained, and a result approximate to the intensity distribution when the gap is exposed at 200 μm is obtained.

  Here, an exposure evaluation method using the exposure evaluation mask of FIGS. 1 to 3 will be described. First, a proximity exposure apparatus 1 will be described with reference to FIGS. 5 and 6 as an example of a multi-head exposure apparatus used in the exposure evaluation method. The proximity exposure apparatus 1 according to the present embodiment floats and supports a substrate (for example, a color filter substrate as a liquid crystal display substrate) W, and transports it in a predetermined direction (X direction in FIG. 5). Each of the plurality of masks M is held, and a plurality (six in the embodiment shown in FIG. 5, each on the left and right sides) are arranged in two rows in a zigzag manner along a direction orthogonal to a predetermined direction (Y direction in FIG. 5). A mask holding unit 11, a mask driving unit 12 that drives the mask holding unit 11, a plurality of irradiation units 14 (see FIG. 6) that are arranged on the top of the plurality of mask holding units 11 and irradiate exposure light; And a control unit 15 for controlling the operation of each operating part of the scan exposure apparatus 1. The mask holding unit 11, the mask driving unit 12, and the irradiation unit 14 constitute one head.

  The substrate transport mechanism 10 includes a floating unit 16 provided in a region for transporting the substrate W in the X direction, that is, a region below the plurality of mask holders 11 and a region extending from the bottom region to both sides in the X direction. And a substrate driving unit 17 that holds the one side in the Y direction (upper side in FIG. 5) and conveys it in the X direction. The levitation unit 16 includes a plurality of air pads 20 that are respectively provided on a plurality of frames 19 and that perform only exhaust or exhaust and intake simultaneously.

  As shown in FIG. 5, the substrate drive unit 17 includes a suction pad 22 that holds one end of the substrate W that is levitated and supported by the levitating unit 16, and includes a motor 23, a ball screw 24, and a nut (not shown). The substrate W is transported in the X direction along the guide rail 26 by the ball screw mechanism 25 which is an X direction transport mechanism. As shown in FIG. 6, the plurality of frames 19 are arranged via another level block 28 on the apparatus base 27 installed on the ground via the level block 18. Further, the substrate W may be transported by a linear servo actuator instead of the ball screw mechanism 25.

  The mask drive unit 12 is attached to a frame (not shown), and is attached to the X direction drive unit 31 that drives the mask holding unit 11 along the X direction, and the tip of the X direction drive unit 31. Is attached to the tip of the Y direction drive unit 32, and the mask holding unit 11 is rotationally driven in the θ direction (around the horizontal plane of the X and Y directions). A θ-direction drive unit 33 and a Z-direction drive unit 34 that is attached to the tip of the θ-direction drive unit 33 and drives the mask holding unit 11 in the Z direction (vertical direction of the horizontal plane composed of the X and Y directions). Accordingly, the mask holding unit 11 attached to the tip of the Z direction driving unit 34 can be driven in the X, Y, Z, and θ directions by the mask driving unit 12. Note that the order of arrangement of the X, Y, θ, and Z direction drive units 31, 32, 33, and 34 can be changed as appropriate. The mask drive unit 12 corrects the relative displacement between the mask M and the substrate W based on the pattern of the substrate W and the mark of the mask M captured by the line camera 35 described later.

  Further, as shown in FIG. 5, the mask M of each mask holding part 11 can be exchanged simultaneously between the upstream and downstream mask holding parts 11a and 11b arranged linearly in the Y direction. A simple mask changer 2 is provided. The used or unused mask M conveyed by the mask changer 2 is transferred to and from the mask stockers 3 and 4 by the mask loader 5. The mask M is pre-aligned by a mask pre-alignment mechanism (not shown) while the mask stocker 3 and the mask changer 2 are transferred.

  As shown in FIG. 6, the irradiation unit 14 disposed on the upper part of the mask holding unit 11 is irradiated with the light source 41 composed of an ultra-high pressure mercury lamp that emits the exposure light EL including ultraviolet rays, and the light source 41. A concave mirror 42 that collects light, an optical integrator 43 having a mechanism that can move in the optical path direction near the focal point of the concave mirror 42, a plane mirror 45 and a spherical mirror 46 for changing the direction of the optical path, and the plane mirror 45 And an optical integrator 43, and a shutter 44 for controlling the opening and closing of the irradiation light path. The light source 41 may be a YAG flash laser or an excimer laser. When the flash light source is used, the control unit 15 does not need to perform opening / closing control of the shutter. The exposure amount is calculated by the product of illuminance and time. In the case of a flash light source, the exposure amount is calculated by the product of illuminance and the number of shots.

  The frame 19 disposed below the mask holding unit 11 has a line camera 35 that is an imaging unit that detects the relative position of the substrate W and the mask M at a position where the window 87 of the mask M can be observed. It is arranged for each of the plurality of mask holders 11. As the line camera 35, one having a known configuration is applied, and a pattern (a black matrix reference line when exposing R, G, B when exposed), a mask M The line camera marks provided on the line CCD are captured in the same field of view, and a line CCD as a light receiving surface provided with a large number of light receiving elements arranged in a straight line, and a substrate W A condensing lens for adding reference lines and marks on the line CCD is provided.

  In such a proximity exposure apparatus 1, the substrate W is floated and held by the air flow of the air pad 20 of the floating unit 16, and one end of the substrate W is attracted by the substrate driving unit 17 and transported in the X direction. Then, while performing the alignment process, the exposure light EL from the irradiation unit 14 is irradiated to the substrate W transported below each mask M through the mask M close to the substrate W, and the pattern of the mask M Is transferred to the resist applied to the substrate W.

  When exposure evaluation is performed using the proximity exposure apparatus 1 described above, at least one of the exposure evaluation masks Ma to Mc is disposed in the plurality of mask holding units 11. Then, the substrate W on which the black matrix BM is formed is transported, and the substrate W is irradiated with the exposure light EL via the exposure evaluation masks Ma to Mc, so that the substrate W is exposed to the exposure evaluation masks Ma to Mc. The pattern is exposed. Further, after developing the substrate W, the pattern exposed and transferred to the substrate W is visually evaluated. Thereby, it is confirmed whether or not streak unevenness has occurred at the boundary portion of any region, that is, how much streak unevenness occurs when there is an exposure amount difference, a positional deviation difference, or a gap difference.

  In such an evaluation, the process conditions such as resist and developer material, resist film thickness, resist drying temperature, drying time, and development time are the same, and exposure held by a single mask holding unit 14 Since the exposure is performed by the evaluation mask and by the single light source 41, only the unevenness due to the shift given to the exposure evaluation mask appears on the substrate W, and the exposure unevenness caused by the apparatus can be clearly grasped.

  In actual exposure, the exposure amount difference, positional deviation difference, and gap difference between the plurality of heads (the mask holding unit 12 and the irradiation unit 14) are adjusted based on the above evaluation results to such an extent that streak unevenness does not occur. Done.

  Furthermore, in actual exposure, if the exposure amount difference, positional deviation difference, and gap difference between multiple heads are already adjusted to the extent that streak unevenness does not occur in the evaluation results, unevenness will occur depending on the material and process conditions. Consider changing materials and process conditions to address reductions.

  Therefore, according to the exposure evaluation masks Ma to Mc of the present embodiment, the first regions a1, a3, a5,... (B1, b3, b5,..., C1, having patterns based on the design values. c3, c5,..., and second regions a2, a4,... having a pattern adjacent to the first region that shifts any one of the exposure amount, position, and gap amount with respect to the design value. .. (b2, b4,..., C2, c4,...), And by visually evaluating the substrate W exposed using the masks Ma to Mc, the exposure amount difference, position It is possible to accurately grasp how much the deviation difference and gap difference affect the exposure unevenness.

  Each of the exposure evaluation masks Ma to Md of this embodiment can be appropriately combined, and can be confirmed effectively even when the cause of exposure unevenness is a combination of position, line width, and gap amount.

  Further, in an exposure apparatus using a flash light source, continuously arranged rectangular patterns are arranged, but the exposure amount can be changed by changing the number of the rectangular patterns.

  In addition, it is preferable that the first area based on the design value is alternately arranged with the second area that gives a deviation caused by the apparatus because it is easy to compare the influence of the deviation on the design value, but the cause of the deviation is confirmed. If possible, the shifted second region may be continuously arranged.

  Furthermore, the number of patterns in each region is arbitrarily set to such an extent that visual confirmation is easy. Further, the evaluation may be performed for any one of R, G, and B after exposure / development, or for three colors after exposure / development.

(Second Embodiment)
Next, an exposure evaluation mask and an exposure evaluation method according to the second embodiment of the present invention will be described.

  As shown in FIG. 7, the exposure evaluation mask Md of this embodiment has a plurality of patterns (rectangular windows) formed in a straight line, and a plurality of first patterns having a pattern p based on the design value. , And a plurality of patterns pd having a pattern pd that shifts at least one of the exposure amount, position, and gap amount (in FIG. 8, exposure amount, ie, line width) with respect to the design value. Two regions d2, d4,... Are alternately arranged. Further, the boundary portions between the first regions d1, d3,... And the second regions d2, d4,... Are inclined at different angles so that gradation is applied.

  Specifically, in the mask Md, as shown in FIGS. 7B and 7C, the line width w of the pattern p of the first regions d1, d3, d5 is set to 100 μm, and the second regions d2, d4 The line width w3 of the pattern pd is set to 102 μm, and the difference in line width is given as a deviation in exposure amount. Further, the inter-pattern distance d of each of the regions d1, d2, d3, d4,. Further, at the boundary portion between the first regions d1, d3,... And the second regions d2, d4,. Has been. At the boundary portion between the first region d1 and the second region d2, the connection position interval l1 is changed by 25 mm, and at the boundary portion between the second region and the first region d3, the connection position interval is changed. The distance between the connection positions is changed by 5 mm at the boundary between the first area d3 and the second area d4.

  Such an exposure evaluation mask Md is evaluated using, for example, the evaluation masks Ma, Mb, Mc of the first embodiment, and as a result, the line width w1 of the second region a2 of the evaluation mask Ma is 102 μm. When it is confirmed that streak unevenness has occurred, it can be confirmed whether the streak unevenness is eliminated by applying a gradation at any inclination angle. Therefore, such an evaluation result is reflected in the pattern shape of the mask M when the colored layer is actually exposed.

  The exposure evaluation mask Md of the present embodiment has a plurality of gradations applied to a single deviation amount. However, a plurality of deviation amounts are formed in a pattern, and gradation is provided for each deviation amount. A plurality of ones with different ways of applying may be formed. In that case, by using the mask, it is possible to confirm at a time whether or not the stripe unevenness is generated at which gradation and at which gradation.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
For example, at the present stage, the evaluation and confirmation of the unevenness of the muscles is performed visually, but may be performed using an inspection apparatus.

  Further, in the present invention, by using the exposure evaluation mask, the degree of exposure unevenness can be grasped under a certain material / process condition. For this reason, the mask for exposure evaluation of the present invention is not limited to the evaluation in the case of performing exposure with a multi-head exposure apparatus provided with a plurality of mask holders, but is exposed with a proximity sequential exposure apparatus having one light source. By using it for the evaluation when doing, the influence of the material and the process can be confirmed.

DESCRIPTION OF SYMBOLS 1 Scan exposure apparatus 11 Mask holding | maintenance part (head)
12 Mask drive (head)
14 Irradiation part (head)
a1, a3, a5, b1, b3, b5, c1, c3, c5, d1, d3 first region a2, a4, b2, b4, c2, c4, d2, d4 second region M masks Ma, Mb, Mc, Md Exposure evaluation mask W substrate

Claims (5)

A first region having a pattern based on a design value;
A second region having a pattern adjacent to the first region to give at least one shift of an exposure amount, a position, and a gap amount with respect to the design value;
A mask for exposure evaluation, comprising: A plurality of the first regions and the second regions are provided so as to be alternately arranged,
2. The exposure evaluation mask according to claim 1, wherein in the plurality of second regions, at least one shift amount of an exposure amount, a position, and a gap amount is different from the design value. A plurality of the first regions and the second regions are provided so as to be alternately arranged,
3. The exposure evaluation mask according to claim 1, wherein a plurality of boundary portions between the first region and the second region are inclined at different angles. 4.   4. The exposure evaluation mask according to claim 1, wherein the pattern of the first and second regions is a linear pattern or a continuous pattern. A substrate transport mechanism capable of transporting a substrate in a reciprocating manner along a predetermined direction; a plurality of mask holders each capable of holding a plurality of masks in a state of being separated from the transported substrate; and the plurality of mask holders And an exposure evaluation method using a proximity scan exposure apparatus that includes a plurality of irradiation units that irradiate exposure light.
The step of holding the mask for exposure evaluation according to any one of claims 1 to 4 in any one of the plurality of mask holding portions;
Irradiating the exposure light to the transported substrate through the exposure evaluation mask, and exposing the pattern of the exposure evaluation mask to the substrate;
Evaluating the pattern transferred and exposed to the substrate;
An exposure evaluation method comprising:

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