JP4529099B2 - Reticle, exposure method and semiconductor device manufacturing method - Google Patents

Description

The present invention is a reticle used in the exposure light, a manufacturing method for an exposure method and a semiconductor device.

  One of projection exposure apparatuses that transfer a pattern drawn on a reticle to a resist is a reduction projection exposure apparatus. In this reduced projection exposure apparatus, a step-and-repeat method is adopted, and a mechanism capable of realizing this method is provided.

  The step-and-repeat method is a method in which exposure is performed every time a wafer on an XY stage that can move in two dimensions is fed in a fixed dimension when a reticle pattern is transferred to a resist. Hereinafter, an exposure method in the reduced projection exposure apparatus will be described.

  FIG. 14 is a view showing a state of exposure of a general reduction projection exposure apparatus. Referring to FIG. 14, light (g-line or i-line) from a mercury lamp is emitted from light source 51 to glass mask (reticle) 210 through condenser lens 50. The light that has passed through the reticle 210 is transferred to the photoresist on the wafer 20 through the reduction projection lens 40.

  In such a reduced projection exposure apparatus, an area that can be exposed at one time (one shot) is, for example, about 20 mm × 20 mm. For this reason, the position of the wafer 20 is automatically and sequentially moved in the X and Y directions by the XY stage 52, and the wafer 20 is exposed for each shot.

The wafer 20 is vacuum-fixed on the XY stage 52.
Next, the configuration of a conventional reticle used in the reduced projection exposure apparatus will be described.

  FIG. 15 is a schematic plan view showing the configuration of a conventional reticle. FIGS. 16 and 17 are partial plan views showing the area P5 and the area P6 in FIG. 15 in an enlarged manner.

  Referring to FIG. 15, this reticle 210 shows a configuration in which a circuit pattern for two chips is formed in one shot. That is, each one of the element formation regions 1A and 1B corresponds to a circuit pattern for one chip. Further, a dicing area 3B is disposed between the element forming areas 1A and 1B, and the element forming areas 1A and 1B and the dicing area 3B constitute a predetermined area 2 having a square planar shape.

  Referring to FIGS. 15 and 16, a relatively wide dicing area 203 </ b> A is arranged so as to contact the left side and the lower side in the drawing of the outline of the predetermined area 2. In this wide dicing area 203A, monitor mark areas of the alignment mark area 5 and the overlay inspection mark area 7 are arranged corresponding to the upper left corner, lower left corner and lower right corner of the predetermined area 2 in the figure. ing. Monitor mark areas 5 and 7 are also arranged in the dicing area 3B.

  Referring to FIGS. 15 and 17, relatively thin dicing areas 203 </ b> C are arranged on the right side and the upper side in the drawing outside the predetermined area 2.

  Referring to FIGS. 15 to 17, an overlap region (slit region) 204 is arranged so as to be in contact with each of a relatively wide dicing region 203 </ b> A and a narrow dicing region 203 </ b> C and to surround the outer periphery thereof. This overlap area 204 is for taking into account a step shift that occurs during exposure by step-and-repeat. A light shielding region 9 is disposed in the outer peripheral region of the dicing regions 203A and 203C and the overlap region 204.

  Next, when this conventional reticle is viewed in a cross section taken along line A3-A3 of FIG. 16, for example, it is as shown in FIG. With reference to FIG. 18A, the reticle 210 includes a transparent substrate 11 and light shielding films 13 and 15 formed on the transparent substrate 11. In the element formation regions 1A and 1B, although not shown, a predetermined circuit pattern is formed by a light shielding film. In the alignment mark area 5, a plurality of alignment mark patterns 13 made of a light shielding film are arranged. A light shielding film 15 is formed on the entire outermost light shielding region 9.

  Next, a process until patterning a film to be etched on a wafer using this conventional reticle will be described.

  The exposure light transmitted through the reticle 210 shown in FIG. 15 is irradiated onto the photoresist applied to the wafer, and exposure for one shot is completed. Thereafter, as shown in FIG. 14, the stage 52 on which the wafer 20 is placed moves and exposure of the next shot is performed. At this time, exposure is performed so that the overlap area 204 (FIGS. 16 and 17) of the already exposed shot and the overlap area 204 of the newly exposed shot overlap each other. This is to prevent an unexposed area from occurring between adjacent shots due to a step shift that occurs during exposure by step-and-repeat.

  In this way, a plurality of shots 260 are exposed on the photoresist as shown in FIG. The shot 260 includes element formation regions 61A and 61B, relatively wide dicing regions 263A and 263B, a relatively narrow dicing region 263c (not shown), and an alignment mark region 65 corresponding to the reticle 210 shown in FIG. And an overlay inspection mark area 67. FIG. 19 shows a state where four shots are exposed. As shown in FIG. 19, after the exposure of each shot 260 to the photoresist is completed, the photoresist is developed to form a resist pattern.

  FIG. 18B is a view corresponding to a cross section taken along line B3-B3 of FIG. 19 of the wafer corresponding to the reticle of FIG. Referring to FIG. 18B, when the photoresist 27 is a positive type, only an unexposed region of the photoresist 27 remains by development. Then, the etching target film 23 is patterned into a predetermined shape by etching the underlying etching target film 23 using the resist pattern 27 as a mask. Thereafter, the resist pattern 27 is removed. Here, the case where the convex alignment mark 23 is formed on the semiconductor substrate 21 in the alignment mark region 65 is shown.

  Further, in FIG. 18B, the photoresist 27 does not remain in the region corresponding to the light shielding region 9 on the wafer. In this region, the element formation region 61B of the adjacent shot and a part of the dicing region are located. Because it will be.

  In general, before exposure, alignment is performed to align the position of the reticle with the position of the wafer in order to overlay the positions of the reticle pattern and the wafer pattern with high accuracy. In this alignment, for example, the position of the alignment mark on the wafer is recognized using diffracted light, and shot rotation and reduction magnification are determined based on this recognition, and the position of the alignment mark on the reticle is set to the position of the alignment mark on the wafer. It is done by matching.

  However, in the conventional reticle, the alignment mark 5 cannot be arranged in the vicinity of the upper right corner of the predetermined region 2 in FIG. For this reason, this misregistration information is lost, and misregistration (that is, shot magnification error, shot rotation error, etc.) is likely to occur in the upper right corner of the shot transferred to the photoresist. There was a problem.

  Further, after the exposure / development, the overlay error between the circuit pattern of the wafer and the resist pattern is usually measured. The overlay error is measured by a known box-in-box method, for example. That is, it is determined whether or not the two patterns are accurately superimposed based on the relative position between the overlay mark formed from the same layer as the circuit pattern on the wafer and the overlay mark formed on the resist pattern. . If the overlay error is within an allowable value, the etching target film is etched using the resist pattern as a mask. If the registration error exceeds the allowable value, the photoresist is applied, exposed and developed again.

  However, with the conventional reticle, the overlay mark 7 cannot be arranged near the upper right corner in FIG. For this reason, as in the case of the alignment mark, the positional information on the corners is lost, and there is a problem that the overlay accuracy is deteriorated due to an error in shot magnification or an error in shot rotation.

  In addition, even if analysis is performed based on the overlay inspection result and the exposure is performed after correcting the alignment, the alignment correction value in the upper right part of the shot cannot be calculated, so that there is a problem that the overlay accuracy is deteriorated. .

  In order to prevent the deterioration of the overlay accuracy, it can be considered that the reticle is configured as shown in FIG.

  Referring to FIG. 20, in this configuration, a relatively thick dicing area 303 </ b> A is arranged on all four sides of the outer shape of rectangular predetermined area 302. In addition, the predetermined area | region 302 is comprised by element formation area 1A, 1B and the dicing area | region 303B pinched | interposed between them like the above.

  Thus, by arranging the relatively thick dicing area 303A on the entire four sides, the monitor mark areas such as the alignment mark area 5 and the overlay inspection mark area 7 are arranged in the vicinity of all four corners of the predetermined area 302. Is possible. Thereby, deterioration of the overlay accuracy due to missing monitor marks 5 and 7 at any one corner of the predetermined region 302 can be prevented.

However, in this case, as shown in FIG. 21, the width W ₀ of the dicing area 363A between shots becomes thick and the area thereof becomes large. For this reason, there is a problem that the plane occupancy of the element formation regions 61A and 61B on the wafer is reduced, and the yield of the semiconductor chip is reduced.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a reticle , an exposure method, and a semiconductor device manufacturing method that can prevent deterioration of overlay accuracy due to shot rotation or shot magnification error without increasing the area of a dicing region. is there.

The reticle of the present invention includes a predetermined area, first and second outer peripheral dicing areas, and an alignment mark area. Predetermined region is comprised of an intermediate portion dicing region sandwiched between the element forming region and the element formation region of multiple, planar shape is a rectangular area. The first outer peripheral dicing region has a planar shape having two or more convex portions arranged in contact with a part of one side forming the opposite side of the rectangular planar shape of the predetermined region. The second outer peripheral dicing region of the are arranged in contact with a portion of the other side forming the opposite side, and the convex portion of the first outer peripheral dicing region is disposed such writing fits in a region not formed 2 It has the planar shape which has the above convex part. The alignment mark regions are arranged in different convex portions of the first and second outer peripheral dicing regions corresponding to all four corners of the square planar shape of the predetermined region.

According to the reticle of the present invention, since the first and second outer peripheral portion dicing regions arranged on opposite sides have the convex portions, the convex portions are formed in the vicinity of all four corner portions of the rectangular predetermined region. And an alignment mark region can be arranged on the convex portion. Therefore, one positional deviation information of the corner portion is not lost, and hence it is possible to prevent deterioration in overlay accuracy due to shot rotation, shot magnification error, and the like.

In addition, the first and second outer peripheral dicing regions have a shape having convex portions that fit into each other and regions where no convex portions are formed . For this reason, when shots are continuously transferred, the second outer peripheral dicing of the other shot is not formed in the region where the convex portion of the first outer peripheral dicing region of one of the adjacent shots is not formed. The convex part of the region is fitted, and the convex part of the first outer peripheral dicing region of one shot is fitted to the region where the convex part of the second outer peripheral dicing region of the other shot is not formed . Therefore, the sum of the widths of the first and second outer peripheral dicing regions should be made smaller than the conventional example in which the widths of the first and second outer peripheral dicing regions are made thick enough to allow alignment marks or the like to be arranged. Can do.
In the above reticle, preferably, an overlay inspection mark region disposed in the convex portion is further provided.
Preferably, in the above-described reticle, the first outer peripheral dicing region has a concave portion that is disposed in a region on one side where the convex portion is not formed and has a narrower width than the convex portion of the first outer peripheral dicing region. The second outer peripheral dicing region has a concave portion that is disposed in a region on the other side where the convex portion is not formed and has a narrower width than the convex portion of the second outer peripheral dicing region, The concave portion and the convex portion of the second outer peripheral portion dicing region are arranged so as to fit into the convex portion and the concave portion of the outer peripheral portion dicing region.

  In the above reticle, preferably, a transparent substrate and a light shielding film formed on the surface of the transparent substrate are further provided, and light shielding is provided on the outer periphery of the first and second outer peripheral dicing regions disposed on the outer periphery of the predetermined region. A film is formed.

  As described above, since the light shielding film is provided on the outer periphery of the reticle, it is possible to prevent double exposure from occurring in the vicinity of the boundary portion between adjacent shots.

  In the above reticle, preferably, at least one of the first and second outer peripheral dicing regions has two or more convex portions or concave portions.

  Thereby, the number of convex portions of the first and second outer peripheral dicing regions can be appropriately set.

  In the above reticle, preferably, the two or more protrusions have protrusions having different widths.

Thereby, the shape of a convex part and the freedom degree of arrangement | positioning can be expanded.
Preferably, in the above-described reticle, the first outer peripheral dicing region includes a first portion having a first length from one end of one side to a first point on one side, and one side from the first point. And a second portion having a second length to the other end. The second outer peripheral dicing region includes a first portion having a second length from one end of the other side to the second point located in the same direction as one end of the one side, and another from the second point. And a second portion having a first length to the other end of the side. The convex portion and the concave portion of the first portion of the first outer peripheral dicing region have a shape that fits into the concave portion and the convex portion of the second portion of the second outer peripheral dicing region, The convex portion and the concave portion of the second portion of the outer peripheral dicing region have a shape that fits into the concave portion and the convex portion of the first portion of the second outer peripheral dicing region.

  As a result, even if another shot adjacent to that shot is shifted by, for example, ½ shot with respect to one shot, the convex and concave portions of the first and second outer peripheral dicing regions are Fit together. For this reason, the sum of the width of the first outer peripheral portion dicing area of one shot and the width of the second outer peripheral portion dicing area of another shot can be reduced.

In the above reticle, preferably, the width of the convex portion of the first outer peripheral dicing region and the second width are in line symmetry with respect to an imaginary line parallel to both of the opposite side and the other side and passing through the center of the predetermined region. The sum of the width of the concave portion of the outer peripheral dicing region and the width of the concave portion of the first outer peripheral dicing region and the width of the convex portion of the second outer peripheral dicing region which are axisymmetric with respect to the virtual line The sum is constant along one side and the other side.

The exposure method of the present invention is an exposure method for transcription patterns Les chicle the wafer surface through projecting shadow lens includes the following steps.

First, exposure light is emitted from a light source. Then, the exposure light is irradiated onto the reticle. Then, the exposure light transmitted through the reticle is projected onto the photoresist on the semiconductor substrate. The reticle has a predetermined area, first and second outer peripheral dicing areas, and an alignment mark area. Predetermined region is comprised of an intermediate portion dicing region sandwiched between the element forming region and the element formation region of multiple, planar shape is a rectangular area. The first outer peripheral dicing region of, and has a planar shape having a beauty recess side in contact, and Oyo 2 or more protrusions that form the opposite sides of the planar shape of a square of a predetermined area. The second outer peripheral dicing region is disposed in contact with the other side forming the opposite side, and has a concave portion that fits into the convex portion and the concave portion of the first outer peripheral portion dicing region, and a planar shape having two or more convex portions. have. The alignment mark regions are arranged in different convex portions of the first and second outer peripheral dicing regions corresponding to all four corners of the square planar shape of the predetermined region. Then, the convex portion of the first outer peripheral dicing area of one shot out of the adjacent one and the other shot fits into the concave portion of the second outer peripheral dicing area of the other shot, and the second shot of the other shot Each shot is exposed so that the convex portion of the outer peripheral dicing area fits into the concave portion of the first outer peripheral dicing area of one shot.

According to the exposure method of the present invention, since the first and second outer peripheral portion dicing regions arranged on opposite sides have a convex portion and a concave portion, the vicinity of all four corners of the rectangular predetermined region Protruding portions can be provided on the alignment mark regions. Therefore, the positional deviation information of any corner is not lost, and therefore deterioration of overlay accuracy due to shot rotation, shot magnification error, and the like can be prevented.

  Moreover, the 1st and 2nd outer peripheral part dicing area | region has a shape which has the recessed part and convex part which mutually fit. For this reason, when shots are continuously transferred, the convex portion of the second outer peripheral dicing region of the other shot fits into the concave portion of the first outer peripheral dicing region of one of the adjacent shots. The convex portion of the first outer peripheral portion dicing area of one shot fits into the concave portion of the second outer peripheral portion dicing region of the other shot. Therefore, the sum of the widths of the first and second outer peripheral dicing regions should be made smaller than the conventional example in which the widths of the first and second outer peripheral dicing regions are made thick enough to allow alignment marks or the like to be arranged. Can do.

  Preferably, in the above exposure method, the reticle further includes an overlap region that is in contact with the first and second outer peripheral dicing regions and is disposed on the entire outer peripheral portion. The exposure is performed so that the overlap region in contact with the first outer peripheral dicing region of one shot and the overlap region in contact with the second outer peripheral dicing region of the other shot overlap each other.

As a result, it is possible to prevent an unexposed area from occurring between shots even if a step shift occurs during exposure of the shots.
A method for manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device that transfers a reticle pattern onto a wafer surface through a projection lens, and includes the following steps.
First, exposure light is irradiated onto the reticle. The exposure light transmitted through the reticle is projected onto the photoresist on the semiconductor substrate. The reticle includes a predetermined area, first and second outer peripheral dicing areas, and an alignment mark area. Predetermined region is comprised of an intermediate portion dicing region sandwiched between the element forming region and the element formation region of multiple, planar shape is a rectangular area. The first outer peripheral dicing region of, and has a planar shape having a beauty recess side in contact, and Oyo 2 or more protrusions that form the opposite sides of the planar shape of a square of a predetermined area. The second outer peripheral dicing region is disposed in contact with the other side forming the opposite side, and has a concave portion that fits into the convex portion and the concave portion of the first outer peripheral portion dicing region, and a planar shape having two or more convex portions. have. The alignment mark regions are arranged in different convex portions of the first and second outer peripheral dicing regions corresponding to all four corners of the square planar shape of the predetermined region. The step of projecting the exposure light onto the photoresist is such that the convex portion of the first outer peripheral dicing region of one of the adjacent shots is fitted into the concave portion of the second outer peripheral dicing region of the other shot. There is a step of exposing each shot so that the convex portion of the second outer peripheral dicing region of the other shot fits into the concave portion of the first outer peripheral dicing region of one shot.
Preferably, in the semiconductor device manufacturing method described above, the reticle further includes an overlap region disposed in contact with the first and second outer peripheral dicing regions and disposed on the entire outer periphery thereof, and the first outer peripheral portion of one shot. The overlap area in contact with the dicing area and the overlap area in contact with the second outer peripheral dicing area of the other shot are exposed so as to overlap each other.

According to the reticle of the present invention, the first and second outer peripheral dicing regions arranged on opposite sides of each other have the convex portion and the region where the convex portion is not formed. Protrusions can be provided in the vicinity of all the corners, and alignment mark regions can be arranged on the protrusions. Accordingly, the positional information on the corners is not lost, and therefore, it is possible to prevent deterioration in overlay accuracy due to shot rotation, shot magnification error, and the like.

In addition, the first and second outer peripheral dicing regions have a shape having convex portions that fit into each other and regions where no convex portions are formed . For this reason, when shots are continuously transferred, the second outer peripheral dicing of the other shot is not formed in the region where the convex portion of the first outer peripheral dicing region of one of the adjacent shots is not formed. The convex part of the region is fitted, and the convex part of the first outer peripheral dicing region of one shot is fitted to the region where the convex part of the second outer peripheral dicing region of the other shot is not formed . Therefore, the sum of the widths of the first and second outer peripheral dicing regions should be made smaller than the conventional example in which the widths of the first and second outer peripheral dicing regions are made thick enough to allow alignment marks or the like to be arranged. Can do.

  In the above reticle, preferably, a transparent substrate and a light shielding film formed on the surface of the transparent substrate are further provided, and light shielding is provided on the outer periphery of the first and second outer peripheral dicing regions disposed on the outer periphery of the predetermined region. A film is formed.

  As described above, since the light shielding film is provided on the outer periphery of the reticle, it is possible to prevent double exposure from occurring in the vicinity of the boundary portion between adjacent shots.

  In the above reticle, preferably, at least one of the first and second outer peripheral dicing regions has two or more convex portions or concave portions.

  Thereby, the number of convex portions of the first and second outer peripheral dicing regions can be appropriately set.

  In the above reticle, preferably, the two or more protrusions have protrusions having different widths.

Thereby, the shape of a convex part and the freedom degree of arrangement | positioning can be expanded.
Preferably, in the above-described reticle, the first outer peripheral dicing region includes a first portion having a first length from one end of one side to a first point on one side, and one side from the first point. And a second portion having a second length to the other end. The second outer peripheral dicing region includes a first portion having a second length from one end of the other side to the second point located in the same direction as one end of the one side, and another from the second point. And a second portion having a first length to the other end of the side. The convex portion and the concave portion of the first portion of the first outer peripheral dicing region have a shape that fits into the concave portion and the convex portion of the second portion of the second outer peripheral dicing region, The convex portion and the concave portion of the second portion of the outer peripheral dicing region have a shape that fits into the concave portion and the convex portion of the first portion of the second outer peripheral dicing region.

  Thereby, even if another shot adjacent to the shot is shifted by, for example, 1/2 shot, the first and second outer peripheral dicing regions are not protruded from each other. Fit together. For this reason, the sum of the width of the first outer peripheral portion dicing area of one shot and the width of the second outer peripheral portion dicing area of another shot can be reduced.

According to the exposure method of the present invention, since the first and second outer peripheral portion dicing regions arranged on opposite sides have a convex portion and a concave portion, the vicinity of all four corners of the rectangular predetermined region Protruding portions can be provided on the alignment mark regions. Therefore, the positional deviation information at the corners is not lost, and therefore deterioration in overlay accuracy due to shot rotation and shot magnification errors can be prevented.

  Moreover, the 1st and 2nd outer peripheral part dicing area | region has a shape which has the recessed part and convex part which mutually fit. For this reason, when shots are continuously transferred, the convex portion of the second outer peripheral dicing region of the other shot fits into the concave portion of the first outer peripheral dicing region of one of the adjacent shots. The convex portion of the first outer peripheral portion dicing area of one shot fits into the concave portion of the second outer peripheral portion dicing region of the other shot. Therefore, the sum of the widths of the first and second outer peripheral dicing regions should be made smaller than the conventional example in which the widths of the first and second outer peripheral dicing regions are made thick enough to allow alignment marks or the like to be arranged. Can do.

  Preferably, in the above exposure method, the reticle further includes an overlap region that is in contact with the first and second outer peripheral dicing regions and is disposed on the entire outer peripheral portion. The exposure is performed so that the overlap region in contact with the first outer peripheral dicing region of one shot and the overlap region in contact with the second outer peripheral dicing region of the other shot overlap each other.

  As a result, it is possible to prevent an unexposed area from occurring between shots even if a step shift occurs during exposure of the shots.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1
FIG. 1 is a plan view schematically showing a configuration of a reticle in the first embodiment of the present invention. 2 and 3 are enlarged partial plan views showing the region P1 and the region P2 in FIG.

  Referring to FIG. 1, this configuration shows a configuration in which circuit patterns for two chips are formed in one shot. That is, each one of the element formation regions 1A and 1B corresponds to a circuit pattern for one chip. The element forming regions 1A and 1B and the dicing region 3B sandwiched between them constitute a predetermined region 2 having a square planar shape. Dicing areas 3 </ b> A and 3 </ b> C are arranged in the outer peripheral area so as to contact each side of the outer shape of the predetermined area 2.

Referring to FIGS. 1 to 3, dicing regions 3 </ b> A and 3 </ b> C have a shape whose width (for example, W _{11 to} W ₁₄ ) varies along the side direction, and has a large convex portion 3 </ b> A (for example, width W ₁₁₎ , and a part) and a width smaller recess 3C of W ₁₄ (e.g. part of the width W _12, W _13).

In addition, the dicing regions 3A and 3C have specifically the following uneven planar shape.
The convex portion 3A of the left dicing area portion arranged on one side (for example, the left side in the figure) that forms the opposite side of the outer shape of the predetermined region 2 The convex portion 3A of the right dicing region portion has a shape that fits in the concave portion 3C and the concave portion 3C of the left dicing region portion.

More specifically, the sum (W ₁₁ + W ₁₂ , W ₁₃ + W) of the width of the left dicing region and the width of the right dicing region at a symmetric position with respect to the virtual line CC passing through the center of the predetermined region 2. ₁₄ ) is constant along the vertical direction in the figure. That is, the relationship of W ₁₁ + W ₁₂ = W ₁₃ + W ₁₄ is established. This relationship can be similarly applied to the upper dicing region portion and the lower dicing region portion arranged in contact with the upper side and the lower side of the predetermined region 2 in the drawing.

  In addition, monitor mark areas such as the alignment mark area 5 and the overlay inspection mark area 7 are arranged on this convex portion so as to correspond to all four corners of the predetermined area 2.

  Moreover, it is preferable that the overlap area | region 4 is arrange | positioned so that the dicing area | region 3A may be touched and the outer periphery may be enclosed. The overlap region 4 is a consideration of a step shift that occurs during exposure by step-and-repeat. A light shielding region 9 is arranged in the outer peripheral region of the dicing region 3A and the overlap region 4.

  The overlap region 4 is not particularly required if the step shift generated during exposure is within an allowable range. For this reason, although FIGS. 2 to 4 show a configuration having an overlap region, there may be a configuration without this overlap region 4.

  Further, in FIG. 1, the uneven shape of the portion having the length L1 located on the right side of the upper dicing region of the outer peripheral dicing regions 3A and 3C is the portion of the lower dicing region portion having the left length L1 in the drawing. The concave / convex shape of the region having a shape that fits into the concave / convex shape and having the length L2 on the left side of the upper dicing region portion in the drawing is that of the region having the length L2 on the right side of the lower dicing region portion in the drawing. It is preferable to have a shape that fits into the irregular shape. Thereby, as will be described later, even if each shot is shifted by ½ shot, the exposure can be performed satisfactorily.

  Next, when the reticle of the present embodiment is viewed in a cross section taken along the line A1-A1 in FIG. 2, for example, as shown in FIG. Referring to FIG. 4A, reticle 10 includes a transparent substrate 11 made of, for example, quartz, and light shielding films 13, 15 made of, for example, chromium. In the element formation regions 1A and 1B, although not shown, a predetermined circuit pattern is formed by a light shielding film. A plurality of alignment mark patterns 13 made of a light shielding film are arranged in the alignment mark region 5. A light shielding film 15 is formed on the entire surface of the light shielding region 9 on the outer periphery of the dicing region 3 </ b> A and the overlap region 4.

Next, the configuration of an exposure apparatus provided with such a reticle will be described.
FIG. 5 is a schematic diagram showing the configuration of the main part of the exposure apparatus. Referring to FIG. 5, this exposure apparatus reduces a pattern on a reticle and projects it onto a photoresist applied to a wafer. The exposure apparatus also includes a reticle 10, an illumination optical system 30 from the light source to the pattern of the reticle 10, and a projection optical system 40 from the pattern of the reticle 10 to the wafer 20.

  The illumination optical system 30 includes a mercury lamp 31 as a light source, a reflecting mirror 32, a fly-eye lens 33, a diaphragm 34, condenser lenses 35, 37, and 39, a blind diaphragm 36, and a reflecting mirror 38. is doing. The projection optical system 40 includes projection lenses 41 and 43 and a specular stop 42.

  In the exposure operation, first, light emitted from the mercury lamp 31 is reflected by the reflecting mirror 32, for example, only g-line (wavelength: 436 nm), and becomes light of a single wavelength. Next, the light enters each of the fly-eye constituent lenses of the fly-eye lens 33 and then passes through the stop 34.

  The light that has passed through the diaphragm 34 passes through the condenser lens 35, the blind diaphragm 36, and the condenser lens 37, and is reflected at a predetermined angle by the reflecting mirror 38. The light reflected by the reflecting mirror 38 passes through the condenser lens 39 and then uniformly irradiates the entire surface of the reticle 10 (FIG. 1) on which a predetermined pattern is formed. Thereafter, the light is reduced to a predetermined magnification by the projection lenses 41 and 43, and the photoresist on the wafer 20 is exposed.

  In addition to the g-line, this exposure apparatus is also used for i-line (wavelength: 365 nm), excimer laser light (krF excimer laser light (wavelength: 284 nm), ArF excimer laser light (wavelength: 193 nm)).

  Next, steps required until the film to be etched of the wafer is patterned using the reticle of this embodiment mode will be described.

  The exposure light transmitted through the reticle 10 shown in FIG. 1 is applied to the photoresist applied to the wafer, and exposure for one shot is completed. After that, as shown in FIG. 14, the stage 52 on which the wafer is placed moves and exposure of the next shot is performed. In this way, a plurality of shots 60 are exposed on the photoresist as shown in FIG.

  Referring to FIG. 6, during this exposure, between adjacent shots, the convex part of the dicing area of one shot is the concave part of the dicing area of the other shot, and the concave part of the dicing area of one shot is the other. The exposure is performed so that the convex portions of the dicing area of the shots fit into each other. Further, the pattern of the alignment mark 65 and the overlay inspection mark 67 corresponding to each corner is exposed on the wide convex portion of the dicing area 63A.

  Further, exposure is performed so that the overlap area 4 (FIGS. 2 and 3) of the shot that has already been exposed and the overlap area 4 of the shot that is newly exposed overlap each other. This is to prevent an unexposed area from occurring between adjacent shots due to a step shift that occurs during exposure by step-and-repeat.

  The shot 60 includes element forming regions 61A and 61B corresponding to the reticle 10, relatively wide dicing regions 63A and 63B, a relatively narrow dicing region 63C (not shown), an alignment mark region 65, An overlay inspection mark area 67 is included. FIG. 6 shows a state in which four shots are exposed.

  After the exposure of each shot 60 is completed, the photoresist is developed to form a resist pattern. FIG. 4B is a view corresponding to a cross section taken along line B1-B1 of FIG. 6 of the wafer corresponding to the reticle of FIG. Referring to FIG. 4B, when the photoresist 27 is a positive type, only an unexposed region of the photoresist 27 remains by development. Then, the etching target film 23 is patterned into a predetermined shape by etching the underlying etching target film 23 using the resist pattern 27 as a mask. Thereafter, resist patterning 27 is removed. Here, the case where the convex alignment mark 23 is formed on the semiconductor substrate 21 in the alignment mark region 65 is shown.

  In FIG. 4B, the photoresist 27 does not remain in the light shielding area of the wafer because the element forming area 61B of the adjacent shot and a part of the dicing area are located in this area. .

  In the case of forming a concave alignment mark, the reticle 10 having the configuration shown in FIG. 7A in the cross section taken along the line A1-A1 in FIG. 2 may be used. Referring to FIGS. 7A and 7B, in the case of using positive photoresist 27, light shielding film 13 is removed only in the region where the alignment mark is to be formed.

  Then, using the reticle 10 of FIG. 7A, the photoresist 27 applied to the wafer of FIG. 7B is exposed and developed. At this time, since the photoresist 27 is a positive type, only the exposed region of the photoresist 27 is removed, and a resist pattern 27 is formed. For this reason, in this resist pattern 27, there is no photoresist only on the alignment mark forming portion. By etching the underlying etching target film 23 using the resist pattern 27 as a mask, a concave alignment mark is formed on the etching target film 23. Thereafter, the resist pattern 27 is removed.

In the present embodiment, the dicing areas 3A and 3C have such a shape that the convex part 3A of one dicing area arranged on the opposite side of the outer shape of the predetermined area 2 fits into the concave part 3C of the other dicing area. ing. Therefore, when shots are transferred side by side as shown in FIG. 6, the width W ₁ of the dicing regions 63A and 63C located between the adjacent shots 60 is made narrower than the width W _{0 of the} conventional example shown in FIG. be able to. Therefore, the yield rate of the semiconductor chips on the wafer increases as compared with the case of using the conventional reticle shown in FIG.

Further, as shown in FIG. 1, the dicing regions 3A and 3C arranged on the outer periphery vary in widths W ₁₁ and W _{12 and} have a convex portion 3A having a large width and a concave portion 3C having a small width. For this reason, by arranging the monitor mark areas 5 and 7 on the convex part 3A having a large width of the dicing area, the monitor mark areas 5 and 7 are arranged corresponding to all four corners of the predetermined area 2. Is possible. Accordingly, the positional deviation information at the corners of the predetermined region 2 is not lost, and therefore it is possible to prevent deterioration in overlay accuracy due to shot rotation, shot magnification error, and the like.

  As shown in FIG. 1, a light shielding film 9 is formed on the outermost periphery of the reticle 10. This is to avoid double exposure with the adjacent shot when the shots are transferred next to each other as shown in FIG.

  As shown in FIGS. 2 and 3, a so-called overlap region 4 is provided in the dicing region 3A with a predetermined width W4. This overlap region 4 is a region where adjacent shots overlap each other. By overlapping the overlapping regions in this way, it is possible to prevent the occurrence of unexposed regions between dicing regions between adjacent shots even when a step shift occurs during exposure by step-and-repeat.

  The dicing region 3A may have two or more convex portions 3A or concave portions 3C. The monitor mark regions 5 and 7 can be arranged corresponding to all four corners of the predetermined region 2, and the convex portion 3A of one dicing region arranged on the opposite side of the predetermined region 2 is the concave portion 3C of the other dicing region. As long as it has a configuration that fits in, the dicing region 3A can be arbitrarily designed.

  Note that, as shown in FIG. 8, exposure may be performed by shifting the lower shot by ½ shot with respect to the upper shot. Also in this case, it is preferable to have the above-described configuration in which the convex portion 63A of one dicing region between the upper shot and the lower shot fits well into the concave portion 63C of the other dicing region.

Embodiment 2
FIG. 9 is a plan view schematically showing the configuration of the reticle in the second embodiment of the present invention. Referring to FIG. 9, in the present embodiment, dicing areas 103A, 103C, 103D arranged on the outer periphery of predetermined area 2 have an uneven shape, and monitor mark areas 5, 7 are formed on the convex portions. Is the same as in the first embodiment in that it is arranged corresponding to all four corners of the predetermined region 2.

The difference is the widths W ₂₃ and W ₂₄ of the dicing area 103D where the overlay inspection mark area 7 is arranged. The widths W ₂₃ and W ₂₄ are narrower than the width W ₂₁ of the dicing region of the portion 103A where the alignment mark region 5 is arranged, and larger than the width W _{22 of the} portion 103C where no marks are arranged. That is, in the present embodiment, the widths of the dicing areas 103A, 103C, and 103D are changed in three stages.

  Since the configuration other than this is substantially the same as that of the first embodiment described above, the same members are denoted by the same reference numerals and description thereof is omitted.

  Further, using the reticle shown in FIG. 9, a plurality of shots 160 are exposed by step-and-repeat as shown in FIG. 12, as in the first embodiment. As a result, the photoresist is exposed to the element formation regions 61A and 61B, the dicing regions 163A, 163B, 163C, and 163D, the alignment mark region 65, and the overlay inspection mark region 67 corresponding to the reticle shown in FIG. Is done.

  Further, as shown in FIGS. 10 and 11, an overlap region 4 may be provided in the outermost peripheral region of the dicing regions 103 </ b> A, 103 </ b> C, and 103 </ b> D as in the first embodiment. This prevents an unexposed area from occurring between dicing areas between adjacent shots even if a step shift occurs during exposure by step-and-repeat.

  Further, since the light shielding film 9 is provided in the outer peripheral area of the dicing area 103A, double exposure is prevented from occurring between adjacent shots as in the first embodiment.

  In the present embodiment, the case where the widths of the dicing regions 103A, 103C, and 103D are changed in three steps has been described. However, the width is not limited to three steps, and may be changed in four steps or more. May change.

  Also in this embodiment, as shown in FIG. 13, even when the transfer is shifted by a half shot, the convex portion and the concave portion of the dicing area of one shot are the concave and convex portions of the dicing area of the other shot. It is preferable that the dicing region 103A is formed so as to fit into the portion.

Also in the present embodiment, as in the first embodiment, the dicing area between the shots transferred to the photoresist fits into the concave part and the convex part, so that the width W ₂ of these dicing areas is as shown in FIG. The width W _{0 of the} conventional example shown in FIG. For this reason, the removal rate of a semiconductor chip can be improved.

  Further, as shown in FIG. 9, the monitor mark regions 5 and 7 can be arranged on the convex portions 103 </ b> A and 103 </ b> D corresponding to all four corners of the predetermined region 2. For this reason, the misalignment information at the corners is not lost, and therefore it is possible to prevent deterioration in overlay accuracy due to shot rotation, shot magnification error, and the like.

  In the first and second embodiments, the configuration in which two element forming regions are arranged has been described. However, the predetermined region 2 may be configured by a single element forming region, and three or more element forming regions may be formed. It may have a region.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

FIG. 2 is a plan view schematically showing a configuration of a reticle in the first embodiment of the present invention. FIG. 2 is a partial plan view showing a region P1 in FIG. 1 in an enlarged manner. FIG. 2 is a partial plan view showing a region P2 in FIG. 1 in an enlarged manner. FIG. 2 is a partial cross-sectional view (a) of the reticle of FIG. 1 and a schematic cross-sectional view (b) of a wafer onto which the reticle pattern is transferred. 1 schematically shows an exposure apparatus provided with a reticle according to the first embodiment. FIG. It is a top view which shows a mode that the photoresist shown in FIG. 1 was exposed to the photoresist of the wafer by step and repeat. FIG. 2 is a partial cross-sectional view (a) of the reticle of FIG. 1 and a schematic cross-sectional view (b) of a wafer onto which the reticle pattern is transferred. It is a top view which shows a mode that the upper shot and the lower shot were exposed by shifting by 1/2 shot. It is a top view which shows roughly the structure of the reticle in Embodiment 2 of this invention. FIG. 10 is a partial plan view showing a region P3 in FIG. 9 in an enlarged manner. FIG. 10 is a partial plan view showing a region P4 in FIG. 9 in an enlarged manner. FIG. 10 is a plan view showing a state in which the reticle shown in FIG. 9 is exposed to the photoresist of the wafer by step-and-repeat. FIG. 6 is a schematic plan view showing a state in which exposure is performed by shifting the lower shot by ½ shot with respect to the upper shot. It is a figure for demonstrating the principle of the exposure in the reduction | restoration projection exposure apparatus by a step and repeat. It is a schematic plan view which shows the 1st example of the conventional reticle. FIG. 16 is a partial plan view showing a region P5 in FIG. 15 in an enlarged manner. FIG. 16 is a partial plan view showing a region P6 in FIG. 15 in an enlarged manner. FIG. 16A is a partial view of the cross section of the reticle shown in FIG. 15 and FIG. 16B is a cross sectional view of the wafer to which the reticle pattern is transferred. FIG. 16 is a plan view showing a state in which the reticle shown in FIG. 15 is exposed on a photoresist of a wafer by step-and-repeat. It is a schematic plan view which shows the 2nd example of the conventional reticle. It is a top view which shows a mode that the reticle shown in FIG. 20 was exposed to the photoresist of the wafer by the step and repeat.

Explanation of symbols

  1A, 1B Element formation area, 3A, 3B, 3C, 103A, 103B, 103C, 103D Dicing area, 5 Alignment mark area, 7 Overlay inspection mark area, 9 Light shielding area.

Claims (12)

And the predetermined region consists of a middle portion dicing region, the planar shape of square sandwiched between multiple element formation region between the element forming region,
A planar first outer peripheral dicing region having two or more convex portions arranged in contact with a part of one side forming the opposite side of the rectangular planar shape of the predetermined region;
It has two or more convex parts arrange | positioned so that it may fit in the area | region in which the said convex part of the said 1st outer peripheral part dicing area | region is not formed, arrange | positioned in contact with a part of other side which makes the said opposite side A planar outer peripheral dicing region;
A reticle comprising: alignment mark regions arranged in the different convex portions of the first and second outer peripheral dicing regions corresponding to all four corners of the rectangular planar shape of the predetermined region.   The reticle according to claim 1, further comprising an overlay inspection mark region disposed in the convex portion. The first outer peripheral dicing region has a concave portion that is disposed in the one side region where the convex portion is not formed and has a narrower width than the convex portion of the first outer peripheral dicing region,
The second outer peripheral dicing region has a concave portion that is disposed in the region on the other side where the convex portion is not formed and has a narrower width than the convex portion of the second outer peripheral dicing region. ,
The said recessed part and said convex part of a said 2nd outer peripheral part dicing area | region are arrange | positioned so that it may fit in the said convex part and the said recessed part of a said 1st outer peripheral part dicing area | region. The described reticle. Having a transparent substrate and a light shielding film formed on the surface of the transparent substrate;
The reticle according to claim 3, wherein the light-shielding film is formed on an outer periphery of the concave portion of the first and second outer peripheral dicing regions disposed on an outer periphery of the predetermined region.   The reticle according to claim 3, wherein at least one of the first and second outer peripheral dicing regions has two or more of the convex portions or the concave portions.   The reticle according to claim 5, wherein the two or more convex portions have convex portions having different widths. The first outer peripheral dicing region includes a first portion having a first length from one end of the one side to a first point on the one side, and the other end of the one side from the first point. A second portion having a second length up to
The second outer peripheral dicing area includes a first portion having the second length from one end of the other side to a second point located in the same direction as the one end of the one side, A second portion having the first length from a second point to the other end of the other side;
The convex portion and the concave portion of the first portion of the first outer peripheral dicing region fit into the concave portion and the convex portion of the second portion of the second outer peripheral dicing region. Has a shape,
The convex portion and the concave portion of the second portion of the first outer peripheral dicing region are fitted to the concave portion and the convex portion of the first portion of the second outer peripheral dicing region. The reticle according to claim 3, which has a shape.   The width of the convex portion of the first outer peripheral dicing region and the second width at a line-symmetrical position with respect to a virtual line passing through the center of the predetermined region parallel to both the one side and the other side forming the opposite side The sum of the width of the concave portion of the outer peripheral dicing region and the width of the concave portion of the first outer peripheral dicing region and the width of the second outer peripheral dicing region which are line-symmetrical with respect to the virtual line. The reticle according to claim 3, wherein a sum with a width of the convex portion is constant along the one side and the other side. An exposure method for transferring a reticle pattern to a wafer surface through a projection lens,
Emitting exposure light from a light source;
Irradiating the reticle with the exposure light;
Projecting the exposure light transmitted through the reticle onto a photoresist on a semiconductor substrate,
The reticle is
And the predetermined region consists of a middle portion dicing region, the planar shape of square sandwiched between multiple element formation region between the element forming region,
And the predetermined area in contact with one side forming opposite sides of the planar shape of square, and the first outer peripheral dicing region of the planar shape having a beauty recess Oyo 2 or more protrusions,
It is disposed in contact with the other side forming the opposite side, and a second outer periphery of the planar shape having the projections and recesses as fitted into the recess and at least two protrusions of the first outer peripheral dicing region Dicing area,
An alignment mark region disposed in each of the different convex portions of the first and second outer peripheral dicing regions corresponding to all four corners of the rectangular planar shape of the predetermined region,
The step of projecting the exposure light onto the photoresist includes the second outer periphery of the other shot in which the convex portion of the first outer peripheral dicing region of the one shot among the adjacent one and the other shot is the second shot. The convex portion of the second outer peripheral dicing region of the other shot fits into the concave portion of the first outer peripheral dicing region of the one shot. And exposing each of the shots to an exposure method. The reticle further includes an overlap region disposed in contact with the first and second outer peripheral dicing regions and disposed on the entire outer periphery thereof,
The overlap area in contact with the first outer peripheral dicing area of the one shot and the overlap area in contact with the second outer peripheral dicing area of the other shot are exposed so as to overlap each other. Item 10. The exposure method according to Item 9. A method of manufacturing a semiconductor device that transfers a reticle pattern onto a wafer surface through a projection lens,
Irradiating the reticle with exposure light;
Projecting the exposure light transmitted through the reticle onto a photoresist on a semiconductor substrate,
The reticle is
And the predetermined region consists of a middle portion dicing region, the planar shape of square sandwiched between multiple element formation region between the element forming region,
And the predetermined area in contact with one side forming opposite sides of the planar shape of square, and the first outer peripheral dicing region of the planar shape having a beauty recess Oyo 2 or more protrusions,
It is disposed in contact with the other side forming the opposite side, and a second outer periphery of the planar shape having the projections and recesses as fitted into the recess and at least two protrusions of the first outer peripheral dicing region Dicing area,
An alignment mark region disposed in each of the different convex portions of the first and second outer peripheral dicing regions corresponding to all four corners of the rectangular planar shape of the predetermined region,
The step of projecting the exposure light onto the photoresist includes the second outer periphery of the other shot in which the convex portion of the first outer peripheral dicing region of the one shot among the adjacent one and the other shot is the second shot. The convex portion of the second outer peripheral portion dicing region of the other shot is fitted into the concave portion of the first outer peripheral portion dicing region of the one shot. A method of manufacturing a semiconductor device, further comprising: exposing each of the shots. The reticle further includes an overlap region disposed in contact with the first and second outer peripheral dicing regions and disposed on the entire outer periphery thereof,
The overlap area in contact with the first outer peripheral dicing area of the one shot and the overlap area in contact with the second outer peripheral dicing area of the other shot are exposed so as to overlap each other. Item 12. A method for manufacturing a semiconductor device according to Item 11.

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