JP4267906B2 - Mask frame and exposure apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mask frame and an exposure apparatus used in a mask manufacturing process which is one of processes for manufacturing a semiconductor device.
[0002]
[Prior art]
In a photolithography process in a manufacturing process of a semiconductor device, a liquid crystal display device or the like, an exposure apparatus that projects and exposes a circuit pattern formed on a mask onto a substrate such as a semiconductor wafer or a glass substrate is used.
[0003]
There is a proximity exposure apparatus as one of the exposure apparatuses, and the proximity exposure apparatus holds and exposes a mask with respect to the substrate. In addition, with the recent increase in size of substrates such as semiconductor wafers and glass substrates, the mask is moved relative to the object to be exposed to perform divided exposure to expose the entire substrate.
[0004]
The outline of the substrate holding part 14 and the mask holding part 15 will be described with reference to FIGS.
[0005]
A mask frame 2 that holds the mask 1 on which a pattern is formed has a frame shape, and abuts on the peripheral portion of the mask 1 from the upper surface side. A vacuum suction groove 3 is formed on the lower surface of the mask frame 2, and the mask 1 is held by sucking the peripheral portion of the mask 1.
[0006]
A movable substrate stage 4 is disposed facing the mask 1, and a substrate 5 is placed on the substrate stage 4.
[0007]
The substrate 5 is exposed through the mask 1 from a light projection system (not shown), the substrate stage 4 is further moved, and the exposure position of the substrate 5 is changed for exposure. Thus, the entire surface of the substrate 5 is exposed.
[0008]
As described above, since the peripheral portion of the mask 1 is held, a phenomenon in which the mask 1 bends toward the central portion due to its own weight occurs, and the bending of the mask 1 is caused between the mask 1 and the substrate 5. The optical position was affected, and the exposure performance was deteriorated.
[0009]
For this reason, there is a mask holding portion having a function of suppressing bending due to the weight of the mask 1. For example, Patent Document 1 (see paragraph 0013, FIG. 2) shows a mask frame of a mask holding portion, and the deflection due to the weight of the mask is corrected by the support mode of the mask peripheral portion.
[0010]
This is outlined in FIG.
[0011]
The frame 6 is provided with a correction unit 7 so as to face each other, and the correction unit 7 corrects the deformation of the mask 1 due to its own weight when the peripheral part of the mask 1 is held. That is, the correction unit 7 has a contact slope 8 such that the peripheral portion of the mask 1 is inclined downward toward the outside, and when the peripheral portion of the mask 1 is held, A bending moment that gives rise to the height is given to cancel the bending moment due to its own weight. In FIG. 7, 9 is a mask table.
[0012]
[Patent Document 1]
JP 2000-31019 A
[Problems to be solved by the invention]
However, the above-described conventional correction of the deflection of the mask 1 has the following problems when the mask 1 and the frame 6 have a rectangular shape.
[0014]
FIG. 8 shows the correction unit 7 at the corner of the frame 6.
[0015]
The contact slopes 8a and 8b in two directions are joined at the corner of the correction unit 7, but the contact slopes are discontinuous at the joining line 8c. Alternatively, even if the joining line 8c portion is smoothly finished, the curved surface connecting the contact slope 8a and the contact slope 8b has a large curvature. For this reason, when the deflection of the mask 1 is corrected by the correction unit 7, a large distortion is generated at the corner of the correction unit 7, and if the distortion at the correction unit 7 spreads to the periphery, the correction force is insufficient. As a result, the exposure performance was affected.
[0016]
In view of such a situation, the present invention suppresses the occurrence of excessive distortion at a corner when a mask, in particular, a rectangular mask, is corrected for bending, and enables unreasonable bending correction.
[0017]
[Means for Solving the Problems]
The present invention relates to a frame-shaped mask frame that adsorbs a peripheral portion of a mask and holds the mask, and relates to a mask frame in which a contact slope of the mask frame that is in close contact with the peripheral portion of the mask is formed by a cubic surface. The contact slope is related to a mask frame having at least two different curvatures, and the mask frame has a rectangular window hole, and the curvature of the contact slope formed on opposite sides of the window hole. And the mask frame has a rectangular window hole, and both ends of the abutting inclined surface are separated from the corners of the window hole. An exposure apparatus comprising a frame-shaped mask frame that holds the mask by adsorbing the peripheral portion of the mask, and the contact slope relates to a mask frame formed so as to gradually increase from both ends of the window hole toward the center. In this regard, the present invention relates to an exposure apparatus in which a contact slope of the mask frame that is in close contact with a mask peripheral portion is formed by a cubic curve, and the contact slope relates to an exposure apparatus having at least two different curvatures, and the mask frame. Has a rectangular window hole, the curvature of the contact slope formed on the opposite sides of the window hole is the same, and the mask frame has a rectangular window hole, Both ends of the contact slope are related to an exposure apparatus located at a position away from the corner of the window hole, and the contact slope is formed so as to gradually increase from both ends of the window hole toward the center. It concerns the device.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
In FIGS. 1 and 2, reference numeral 6 denotes a frame having a rectangular window hole 11 for exposure. In addition, in the figure, the same code | symbol is attached | subjected to the thing equivalent to what was shown in FIGS.
[0020]
A contact slope 8a is formed along each short side 12a constituting the rectangular shape 12 of the window hole 11, a contact slope 8b is formed along each long side 12b, and the contact slope 8a, the contact The slope 8b is a cubic curved surface such as a spherical surface.
[0021]
The contact slope 8a gradually increases in width from a position spaced from the vertex of the rectangular shape 12 toward the center of the required amount, reaches a maximum at the center, and ends at a position spaced from the corresponding vertex toward the center by the required amount. The bow shape gradually decreases.
[0022]
Similarly, the contact slope 8b gradually increases in width from a position away from the vertex of the rectangular shape 12 toward the center of the required amount, reaches a maximum at the center, and is spaced away from the corresponding vertex by the required amount toward the center. A bow shape that gradually decreases until the end. Thus, the contact slope 8 is not formed around the corner of the rectangular shape 12, and the lower surface (corner peripheral surface 6a) of the frame 6 is widened.
[0023]
A groove 3 is engraved in a similar shape concentrically with the rectangular shape 12, and the groove 3 is formed across the contact slope 8a, the contact slope 8b, and the corner peripheral surface 6a.
[0024]
The groove 3 is connected to a vacuum exhaust device (not shown).
[0025]
Hereinafter, the operation will be described.
[0026]
When the mask 1 is held on the frame 6 by vacuum suction, the peripheral short side portion of the mask 1 is in close contact with the contact slope 8a, and the peripheral long side portion of the mask 1 is in close contact with the contact slope 8b. When the peripheral part of the mask 1 is brought into close contact with the contact slope 8a and the contact slope 8b, the peripheral part of the mask 1 is given a displacement (inclination) that raises the central part.
[0027]
Since both ends of the contact slope 8 a and the contact slope 8 b are positioned before the apex of the rectangular shape 12, the corner of the mask 1 is in close contact with the peripheral surface 6 a of the corner by the groove 3. Thus, the displacement (inclination) of the mask 1 at the corner peripheral surface 6a is 0, and the displacement of the mask 1 given by the contact slope 8a and the contact slope 8b is from the state of displacement 0, respectively. Since it begins, excessive distortion does not occur at the corners of the mask 1. Further, the peripheral portion of the mask 1 is displaced by the contact slope 8a and the contact slope 8b, so that the corner portion of the mask 1 is lifted from the corner peripheral surface 6a. By causing the corners of the mask 1 to be in close contact with the corner peripheral surface 6a, an action of correcting the bending due to the weight of the mask 1 occurs.
[0028]
FIG. 3 shows a state in which the deflection due to the weight of the mask 1 is corrected according to the present invention.
[0029]
By correcting the deflection from the periphery of the mask 1, the vertical deflection of the mask 1 is a minute displacement.
[0030]
About the amount of inclination (curvature) of the contact slope 8a and the contact slope 8b, an optimum value is obtained by calculation, experiment, etc., depending on the size of the mask 1.
[0031]
The curvatures of the contact slope 8a and the contact slope 8b may be different, the contact slope 8a and the contact slope 8b may be the same curvature, and the centers of curvature may be different, or the same curvature and the same curvature. It may be the center. Further, the cubic curved surface may be a part of the curved surface of the sphere or a part of the curved surface of the elliptic sphere.
[0032]
【The invention's effect】
As described above, according to the present invention, in the frame-shaped mask frame that holds the mask by adsorbing the peripheral portion of the mask, and the mask frame that is in close contact with the peripheral portion of the mask in the exposure apparatus having the mask frame. The abutting slope is formed with a cubic curved surface, and the abutting slope is formed so as to gradually increase from both ends toward the center, so there is no portion where excessive distortion occurs over the entire circumference of the mask, This makes it possible to correct the deflection of the mask without unreasonableness, and exhibits an excellent effect of improving the exposure performance.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of the present invention.
FIG. 2 is a front sectional view showing the embodiment of the present invention.
FIG. 3 is an explanatory view showing an operation of the embodiment of the present invention.
FIG. 4 is a plan view showing a substrate holding part and a mask holding part of the exposure apparatus.
FIG. 5 is a front sectional view showing a state where a mask is held.
6 is an AA arrow view of FIG. 4;
FIG. 7 is a cross-sectional view showing a conventional mask holding unit.
FIG. 8 is an explanatory diagram of a corner portion of a conventional mask frame.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mask 2 Mask frame 3 Groove 4 Substrate stage 5 Substrate 8a Contact slope 8b Contact slope 11 Window hole

Claims (6)

In a frame-shaped mask frame for holding the mask by adsorbing mask peripheral portion, the mask frame has a window opening of a rectangular shape, on the mask periphery along each side of the window hole abutment slope close contact is formed, the abutting slope increases the width from the position away a predetermined amount from both ends of each side of the rectangular shape of the window hole is gradually, arcuate as the width at the center is the largest of the sides A mask frame, characterized in that it is a cubic surface that imparts a displacement to the mask peripheral part so as to raise the central part of the mask.   The mask frame according to claim 1, wherein the contact slope has at least two different curvatures.   The mask frame according to claim 1, wherein the curvature of the contact slope formed on opposite sides of the window hole is the same. The mask peripheral portion adsorbed at the exposure apparatus comprising a frame-shaped mask frame for holding the mask, said mask frame has a window opening of a rectangular shape, along each side of the window hole abutting slope is formed in close contact with the mask periphery, the abutment slope gradually increases from a position a predetermined amount away from both ends of each side of the rectangular shape of the window opening, like the width at the center of the side is maximum An exposure apparatus, wherein the exposure apparatus is a cubic curved surface that is formed in a bow shape and imparts a displacement to the mask peripheral portion so as to raise the central portion of the mask .   The exposure apparatus according to claim 4, wherein the contact slope has at least two different curvatures.   The exposure apparatus according to claim 4, wherein the curvature of the contact slope formed on opposite sides of the window hole is the same.

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